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Dwarf Galaxias (Galaxiella pusilla)

The dwarf galaxias is a very small, non-migratory freshwater fish of shallow, slow-flowing or still wetlands, drains, swamps, streams and creek backwaters in south-eastern Australia. Its habitat is often temporary and depends on suitable vegetation, natural wetting and drying cycles, and intermittent connection to more permanent waterbodies, so clearing, drainage, altered flows, sediment runoff and introduced fish can affect local populations quickly.

Conservation status

Commonwealth, EPBC Act 1999: Endangered.

Victoria, Flora and Fauna Guarantee Act 1988: Endangered.

Breeding season

The timing below describes a typical southern Australian year. Local timing varies with rainfall, water temperature, latitude and wetland hydroperiod. Sampling in Victoria is generally most effective from December to April, with March to May also identified as a useful drier period.

Avoid interpreting a dry wetland as unoccupied. The species can persist through drying using moist habitat features, and seasonal flooding is needed to replenish temporary sites.

  • Breeding and egg laying: Spawning is reported from late autumn to spring, with August and September identified as a common spawning period. Females lay adhesive eggs over 7 to 14 days.
  • Eggs and larvae: Eggs hatch after about 2 to 3 weeks. Larvae are about 4.5 mm at hatching.
  • Juvenile recruitment: The species appears to have one year class. Juveniles recruit following the breeding period, but the exact timing varies with local conditions.
  • Flood assisted dispersal: The species is non-migratory, but flooding and shallow flowing connections allow dispersal between permanent, seasonal and ephemeral waterbodies. Timing depends on rainfall and local flooding.
  • Summer drying and refuge use: Some occupied wetlands partially or completely dry during summer. Fish may use moisture-retaining vegetation and freshwater crayfish burrows during dry periods.
  • Highest clearing risk: Clearing or disturbance is most likely to harm the species from late autumn through spring because spawning, eggs, larvae and recruitment may be affected. Disturbance of dry wetlands in summer can also damage refuge habitat and should not be treated as low risk.

Identification

The dwarf galaxias is a tiny, scaleless galaxiid fish that is usually found close to dense aquatic or emergent vegetation. Identification should be undertaken by an experienced freshwater fish ecologist, particularly where the taxon may have been confused with the little galaxias following the 2015 taxonomic revision.

The body is small, slender to stocky and elongated, with an olive-brown to olive-amber back and upper sides, a silver-white underside and transparent fins. It has no scales, all soft-rayed fins, a single dorsal fin positioned well back on the body, and a rounded caudal fin with fleshy flanges extending forwards towards the dorsal and anal fins.

Three dark longitudinal stripes may be visible along each side of the body. Spawning males have a conspicuous bright orange-red stripe between the lower two dark stripes. Females generally have a thinner silver, gold, pale mauve or pale orange stripe.

Maximum reported female length: About 47 mm total length

Maximum reported male length: About 37 mm total length

Typical water depth: About 0.5 to 1.5 m

Identification: Separating similar species

The dwarf galaxias does not normally co-occur with other Galaxiella species, which reduces the chance of confusion at a known site. The main comparison is the little galaxias, Galaxiella toourtkoourt, which was separated from the former broad concept of G. pusilla after genetic and morphological work.

Compared with the little galaxias, the dwarf galaxias is generally larger, has a slightly longer caudal peduncle, and has a more pronounced setback between the dorsal and anal fins, especially in females. Confirm identifications using an appropriate taxonomic key or specialist advice where the range of both taxa could be relevant.

Identification: Field detection and handling

There are no reliable terrestrial field signs such as tracks, scats, calls, nests or sloughs. Fish may be seen in shallow water close to emergent or submerged vegetation, but direct detection can be difficult in dense cover.

For project surveys, small scoop nets, dip nets and small collapsible traps are suitable options in shallow vegetated habitat. Overnight collapsible traps have been reported as effective for eastern dwarf galaxias where cover is dense or conductivity limits backpack electrofishing. Electrofishing can provide more quantitative information, but must be undertaken by appropriately qualified personnel under approved animal ethics and fish handling procedures.

The fish should be released promptly at the point of capture unless collection is authorised for an approved translocation, genetic or captive-breeding program.

Recommended Victorian survey window: December to April, with March to May also identified as a drier period that may improve capture chances.

  • Map all permanent, semi-permanent, seasonal and ephemeral waterbodies in the project area and downstream impact area before selecting survey locations.
  • Include shallow margins, drains, swamps, creek backwaters and dense aquatic vegetation rather than sampling only the main channel.
  • Use an experienced fish ecologist to confirm small Galaxiella specimens.

Distribution: Current national range

The current taxonomic concept has a disjunct distribution in coastal Victoria, Flinders Island and northern Tasmania. Earlier records extending farther west, including South Australia and western Victoria, may include the separate little galaxias, G. toourtkoourt, and should not be assigned to the dwarf galaxias without taxonomic confirmation.

In Victoria, the dwarf galaxias is currently recorded from the Mitchell River Basin near Bairnsdale west to Dandenong Creek in Greater Melbourne. It also occurs on Flinders Island and in north-eastern and north-western Tasmania.

The species occurs in lowland coastal and near-coastal freshwater systems rather than a single continuous river network. The supplied documents describe the range by river basins, catchments, islands and coastal regions, rather than by formal IBRA bioregion names.

  • Victoria: Mitchell River Basin, Gippsland and coastal Victorian catchments west to Dandenong Creek and the Greater Melbourne area.
  • Tasmania: lowland sites in the north-east and north-west, plus Flinders Island in Bass Strait.
  • South Australia and south-western Victoria: older range information requires caution because of the later separation of G. toourtkoourt.

Distribution: Known strongholds and management units

The distribution is patchy and disjunct. The current assessment identifies approximately 50 sites across the revised range, while the earlier national recovery plan recorded about 110 populations before the taxonomic revision and broader historical treatment.

Twelve genetically inferred management units are identified as important for retaining genetic diversity. These include Flinders Island, Big Waterhouse Lake, Icena Creek, Harcus River, Darby River, Flooding Creek, the Port Phillip and Western Port grouping, Monkey Creek, the Cobblers Creek grouping, Merriman Creek, Deep Creek and Perry Creek.

Permanent creeks and rivers are particularly important as source populations for replenishing nearby ephemeral habitat and supporting dispersal during flooding.

Approximate current site count in the revised range: About 50 sites

Earlier population estimate: About 110 populations before the taxonomic revision and broader historical treatment

Genetically inferred management units: 12

Translocated Victorian population: La Trobe University wildlife reserve, Bundoora, sourced in the early to mid 1990s from Tirhatuan Wetland, Rowville

  • Treat each confirmed population as important where it represents a genetically distinct management unit, a range extreme, a high-density site, an isolated site or a permanent-water source population.
  • Check historical records carefully because several Victorian and Tasmanian localities have been reported as extirpated.

Distribution: Population trend

The species was almost certainly more widespread and abundant before extensive wetland drainage and modification. The revised distribution was reduced by about 60 percent after the former species concept was split into two species.

Population abundance can vary greatly between seasons and years because sites may dry naturally. The available assessment identifies a continuing decline in geographic range through habitat loss, fragmentation and degradation, but does not provide a reliable national estimate of mature adult abundance or a measured trend over three generations.

Reliable national mature adult population estimate: Not available in the supplied documents

Documented revised range reduction: About 60 percent

Historical decline cited for parts of Victoria: Up to 90 percent in some areas, particularly through loss and degradation of shallow wetlands

Habitat: Waterbodies and vegetation

Dwarf galaxias habitat is shallow freshwater with cover, low to slow flow and a natural pattern of wetting and drying. Sites may be natural or artificial and may be permanent, semi-permanent, seasonal or ephemeral.

The species occurs in slow-flowing streams and creeks, backwaters, swamps, marshes, drains and other shallow wetlands. It is usually associated with dense emergent and submerged aquatic vegetation, including vegetation along the margins of larger pools.

The fish can tolerate a broad range of recorded water conditions, but habitat suitability depends on the combined availability of water, cover, food and connectivity. Fast-flowing, heavily engineered channels with little vegetation are less suitable than shallow vegetated habitat.

Typical depth: About 0.5 to 1.5 m

Typical elevation: About 25 to 72 m above sea level

Recorded temperature tolerance: 5.8 to 24.8 degrees Celsius

Recorded pH range: 5.0 to 7.8

Recorded turbidity range: 1 to 133 NTU

  • Retain shallow wetland depressions, creek backwaters, drains and off-channel pools connected to known habitat.
  • Retain emergent and submerged vegetation, marginal rushes and sedges, fallen timber and other cover within and beside the water.
  • Avoid filling or reshaping temporary wetlands during dry periods, when habitat may be difficult to recognise.

Habitat: Hydrological structure

The species has a metapopulation structure. Persistence depends on a network of permanent, semi-permanent, seasonal and ephemeral waterbodies that can reconnect during floods or other wet periods.

Seasonal drying is a normal feature of some occupied wetlands, but extended drying without access to refuge habitat or replenishment from a permanent waterbody can cause local loss. Hydrologically connected waterways with suitable substrate, riparian vegetation and water quality within 25 km of known sites are identified as potential habitat for natural migration or future translocation.

  • Maintain natural wetting, drying and flooding patterns where practicable.
  • Protect shallow connections between wetlands and permanent creeks or rivers.
  • Assess upstream water extraction, drainage, stormwater concentration, culverts and barriers as part of the habitat footprint.

Foraging habitat: Food

Dwarf galaxias feed within shallow freshwater habitat, especially around aquatic vegetation and the margins of pools and slow-flowing channels. No quantified individual foraging range is available in the supplied documents.

The diet consists mainly of tiny aquatic invertebrates, including chironomid larvae, copepods, cladocerans and ostracods. Terrestrial insects that fall onto the water surface are also eaten.

Some sources describe the species as a generalist carnivore and report observations of filamentous algae in the diet, but the principal documented food items are aquatic invertebrates.

Foraging range: Not quantified in the supplied documents

  • Retain aquatic vegetation and organic cover that support aquatic invertebrates.
  • Prevent sediment, nutrient and chemical runoff that can reduce aquatic invertebrate habitat and water quality.
  • Maintain riparian vegetation for shade, litter input, bank stability and terrestrial insect fall.

Foraging habitat: Foraging locations

The fish is a mid-water, free-swimming species, but it commonly stays close to the edge of waterbodies where submerged and emergent vegetation provides cover. In larger pools, it is usually found among marginal vegetation.

Sedimentation can reduce food availability by blanketing the bed and reducing aquatic plants and macroinvertebrates. Trampling and removal of riparian vegetation can also increase temperature, turbidity and nutrient inputs.

Breeding habitat: Breeding biology

Breeding occurs entirely in freshwater and is associated with aquatic vegetation or firm submerged surfaces in shallow wetlands, streams, drains and creek backwaters. Annual recruitment appears important because adults may die after spawning.

Females attach adhesive eggs singly to the underside of aquatic vegetation or to hard surfaces such as submerged rocks, timber or logs. Up to three males may attend a female and pass over the eggs to fertilise them.

Larvae hatch after about 2 to 3 weeks. Only one year class has been observed, and adults have been observed dying after spawning, supporting an annual life cycle. A failed breeding season may therefore have a large effect on a local population.

Breeding season: Late autumn to spring; spawning is also reported particularly in August and September

Eggs per female: About 65 to 250 adhesive eggs

Egg laying period: About 7 to 14 days, with eggs laid one at a time

Incubation and hatching: Larvae hatch after about 2 to 3 weeks

Age at maturity: Not reported in the supplied documents

Lifespan: Likely about one year; adults may die after spawning

Breeding habitat: Breeding habitat features

Breeding habitat requires shallow freshwater with aquatic vegetation or submerged hard surfaces for egg attachment. Water levels and flow must remain suitable through spawning, egg development and larval emergence.

The surrounding wetland network also matters. Seasonal flooding and connection to permanent waterbodies allow recruitment and replenishment of ephemeral sites, particularly after drying.

  • Avoid clearing or removing submerged and emergent vegetation during the late autumn to spring breeding period.
  • Prevent sediment deposition on egg attachment surfaces and shallow nursery habitat.
  • Maintain hydrological connection between breeding wetlands and permanent source populations where that connection is part of the local system.

Sheltering habitat: Aquatic cover

Cover is provided mainly by aquatic and riparian vegetation, submerged structure and, during drying, moisture-retaining refuges such as freshwater crayfish burrows. The supplied documents do not give dimensions for burrows or a minimum cover area.

Dwarf galaxias commonly remain close to emergent and submerged vegetation, particularly along the margins of pools and wetlands. Vegetation provides concealment, moderates water temperature and supports food resources.

Suitable cover may occur in natural wetlands, slow-flowing streams, drains and constructed wetlands. Removing vegetation, converting natural banks to concrete or increasing flow velocity can reduce shelter even where water remains present.

  • Retain dense aquatic vegetation and intact vegetated margins during site preparation and construction.
  • Use exclusion zones to prevent machinery access, stock trampling and sediment entry into shallow vegetated habitat.
  • Retain riparian shade and litter inputs around occupied and connected habitat.

Sheltering habitat: Dry-period refuges

During drying, the species can survive periods without surface water by using moist habitat features, including burrows made by freshwater crayfish. The exact degree of dependence on crayfish burrows and the duration of survival in them remain uncertain.

Trampling, drainage, altered water tables, pesticide impacts and introduced crayfish can reduce the availability or condition of these refuges.

  • Protect crayfish burrows and moist ground around occupied ephemeral wetlands from grading, compaction, stock access and vehicle traffic.
  • Do not assume a dry wetland is unoccupied without considering subterranean or moisture-retaining refuges.
  • Assess impacts on freshwater crayfish habitat where dry-season refuge is likely to be part of the local population's survival strategy.

Threats: Clearing, filling and fragmentation

The main project risks are direct loss of shallow freshwater habitat, changes to water levels and flows, fragmentation of wetland connections, sediment and water quality impacts, and introduction or spread of predatory or competing species.

Shallow wetlands, swamps, drains, creek backwaters and riparian vegetation have been lost or modified through agricultural, urban and industrial development. Filling or draining a wetland can remove habitat directly, while roads, culverts, channels and construction compounds can disconnect temporary habitat from permanent water.

Fragmentation is particularly serious because the species is short-lived, has poor recolonisation ability and depends on connected waterbodies for replenishment after drying or local extinction.

  • Treat occupied sites, former sites, connected wetlands and suitable habitat within the local hydrological network as part of the assessment area.
  • Avoid direct habitat loss and retain wetland and riparian buffers through design changes where practicable.
  • Keep construction access, spoil, laydown areas and dewatering discharge out of shallow wetlands and connected waterways.

Threats: Hydrology and water quality

Surface and groundwater extraction, drainage, dams, channelisation, piping, irrigation regulation and stormwater changes can alter the timing, depth and duration of flooding and drying. These changes can prevent replenishment, reduce refuge habitat and cause local extirpation.

Stock access, earthworks and loss of riparian vegetation can increase turbidity, sedimentation, nutrient inputs and water temperature. Sediment can smother eggs, reduce aquatic invertebrates and blanket stream beds.

  • Maintain natural flow paths, seasonal inundation and connection to permanent water where these support the population.
  • Control turbid runoff, sediment laden water, concrete washout, hydrocarbons and other construction pollutants.
  • Fence or otherwise exclude stock from occupied wetlands and provide off-stream watering points where relevant.
  • Assess both direct dewatering and downstream changes to wetland hydroperiod.

Threats: Introduced species

Eastern gambusia, redfin perch, brown trout, rainbow trout, goldfish, oriental weatherloach and common carp may prey on, compete with or degrade dwarf galaxias habitat. Introduced common yabbies may damage vegetation and increase turbidity, particularly in Tasmania.

Floods can increase connectivity and allow invasive fish to enter previously isolated habitat. Periodic drying may disadvantage eastern gambusia in some systems, but this does not remove the need to prevent introductions.

  • Prevent transfer of fish, water, mud and aquatic equipment between catchments unless equipment is cleaned and disinfected under an approved aquatic biosecurity procedure.
  • Do not stock or translocate fish or crayfish into occupied or connected habitat without appropriate approvals and risk assessment.
  • Consider invasive fish control where predators or competitors threaten a small or isolated population.

Threats: Climate, fire and collection

Hotter and drier conditions, reduced cool-season rainfall, more frequent drought and altered flood patterns are expected to reduce shallow freshwater habitat and recruitment. A drought that prevents breeding for more than one year may have a severe effect on an annual population.

Fire can affect aquatic habitat indirectly through increased water temperature, altered water chemistry and post-fire ash and sediment runoff. Sediment slugs may travel downstream well beyond the burnt area. Unauthorised aquarium collection is also a possible threat to small, restricted populations.

  • Protect refuge wetlands and permanent source populations during drought planning and water allocation decisions.
  • After fire or planned burning, manage ash, sediment and runoff before it reaches occupied waterways.
  • Do not publicise precise locations of small populations where disclosure could increase collection risk.

Survey methodology: 1. Map habitat and plan the survey

Survey all shallow freshwater habitat that could support Dwarf Galaxias before works begin. This includes slow-flowing streams and creeks, swamps, marshes, drains, backwaters and seasonal or ephemeral wetlands, especially where dense emergent or submerged vegetation is present. [Do not write source ids in text]

Define the project area and all areas that could be affected indirectly, including downstream waterways and wetlands.

Map shallow freshwater habitat, aquatic and riparian vegetation, permanent and temporary waterbodies, drainage lines, barriers and connections to more permanent creeks or rivers.

Treat habitat within 25 km of a known site as potential habitat where it is hydrologically connected and has suitable substrate, riparian vegetation and water quality.

Include habitat that may dry during summer, because Dwarf Galaxias populations use networks of permanent, semi-permanent, seasonal and ephemeral waterbodies.

Survey methodology: 2. Targeted trapping in shallow vegetated habitat

Survey from December to April in Victoria, and from March to May in southern states, when flows are lower and conditions are generally drier for fish sampling.

Set small collapsible traps overnight, using phosphorescent chemical sticks as bait where appropriate.

Place traps among dense aquatic vegetation, along shallow margins and in areas where conductivity is too high for backpack electrofishing.

Use traps as a targeted method rather than relying on a general aquatic assessment, because Dwarf Galaxias can be inconspicuous and remain close to cover.

Preferred Victorian survey period: December to April

Preferred southern Australian survey period: March to May

Trap duration: Overnight sets

Survey methodology: 3. Scoop-netting and electrofishing

Use small scoop nets in shallow water with dense aquatic or emergent vegetation, where this method is less likely to harm individual fish than electrofishing.

Use backpack electrofishing where the waterbody and conductivity are suitable, and operate equipment under the Australian Code of Practice with the lowest effective settings and appropriate animal welfare controls.

For general galaxiid sampling, standardise electrofishing time between sites so results can be compared; the survey guidance specifies at least 30 minutes for streams and lake shores in its Tasmanian galaxiid protocols.

Survey shallow margins, backwaters, drains and vegetated edges rather than only open water.

General galaxiid electrofishing effort: At least 30 minutes per stream or lake-shore site

Preferred lower-impact method: Small scoop nets

Survey methodology: 4. Check seasonal and drying conditions

Inspect seasonal wetlands and shallow drains during suitable wet conditions as well as during the drier survey period, because occupancy can change with wetting and drying cycles.

Record whether the site is permanent, semi-permanent, seasonal or ephemeral, and whether it connects to a permanent creek or river during flooding.

Record aquatic vegetation, water depth, flow, turbidity, water quality observations, crayfish burrows and introduced fish observed during the survey.

Do not conclude that a site is unoccupied from one unsuccessful visit where habitat is suitable, because abundance can fluctuate substantially between seasons and years.

Survey methodology: Minimum effort and reporting

  • Use an aquatic fauna ecologist or suitably experienced fish surveyor to select methods, set equipment and identify captured fish.
  • Record survey dates, start and finish times, weather, waterbody type, water level, flow, water quality observations, methods, effort, trap locations, electrofishing time and all captures or non-detections.
  • Record the location of every detection with accurate coordinates, photographs where permitted, habitat photographs and the number and life stages observed.
  • Submit verified records to the relevant state wildlife or biodiversity database, such as the Victorian Biodiversity Atlas in Victoria, and provide records required by project approvals.
  • Retain permits, ethics approvals, equipment settings, animal handling records and a map of surveyed and unsurveyed habitat in the project file.

Before habitat disturbance: Avoid and minimise impacts

Treat suitable shallow freshwater habitat as potential Dwarf Galaxias habitat until targeted surveys and the relevant authority confirm otherwise. The species is nationally listed as Endangered in the supplied assessment and is listed as Endangered in Victoria. [Do not write source ids in text]

  • Avoid filling, draining, piping, concreting or otherwise removing shallow wetlands, swamps, drains, backwaters and slow-flowing creek margins.
  • Retain dense emergent and submerged aquatic vegetation, native riparian vegetation, natural substrates and crayfish burrows where present.
  • Retain intermittent connections between seasonal or ephemeral waterbodies and permanent creeks or rivers, particularly where those connections support replenishment or dispersal.
  • Avoid works that alter the timing, volume or direction of surface water, groundwater, flooding or drying cycles.
  • Keep sediment, nutrients, chemicals and turbid runoff out of occupied and potential habitat, including from works upstream or upslope.
  • Where avoidance is not possible, redesign the works footprint and staging to retain the most connected habitat and permanent source populations.

Before habitat disturbance: Check approvals and plan the works

Spawning period: Late autumn to spring, variable

Critical connected habitat guidance: Hydrologically connected suitable waterways within 25 km of known sites

  • Check whether the action may have a significant impact on this nationally listed species or its habitat and obtain advice on whether an EPBC Act referral is required.
  • Check state and territory threatened-species, fisheries, animal-welfare, wildlife handling, waterway and translocation requirements before capture, relocation or habitat disturbance.
  • Engage the relevant state agency, waterway manager and land manager early, especially where the site is on private land or crosses several tenures.
  • Schedule in-channel and wetland disturbance outside the late autumn to spring spawning period where practicable, while still completing surveys in the species' recommended detection periods.
  • Prepare a fauna management plan that identifies habitat, survey effort, authorised personnel, capture and release procedures, stop-work triggers, water-quality controls, contingency habitat and reporting requirements.

Before habitat disturbance: Prepare and mark the site

  • Complete a targeted pre-clearance aquatic fauna survey before machinery enters or alters suitable habitat.
  • Delineate wetlands, stream margins, aquatic vegetation, riparian vegetation, crayfish burrows, refuge pools, flow paths and retained habitat on construction plans and on the ground.
  • Install exclusion fencing or other controls where they can keep machinery, spoil, vehicles, stock and people out of retained wetlands and waterway margins.
  • Locate access tracks, compounds, stockpiles, dewatering points and sediment controls outside retained habitat and its surface-water connections.
  • Brief all operators and spotter catchers on the species' small size, shallow vegetated habitat, annual life cycle and the requirement to stop if fish or occupied habitat is found.

During habitat disturbance: Daily controls and machinery interface

Maintain aquatic habitat and water quality throughout the works. A fauna spotter catcher must not treat a wetland or vegetated drain as ordinary ground because Dwarf Galaxias may be present at the margins, in shallow pools or in connected refuge habitat. [Do not write source ids in text]

  • Inspect exclusion fencing, silt controls, diversion structures, dewatering areas and retained habitat before work starts each day and after heavy rain.
  • Keep machinery, spoil, concrete washout, fuels, herbicides and sediment-laden water away from wetlands, drains, creeks and riparian vegetation.
  • Use a fauna spotter catcher with aquatic fauna experience to inspect each work area immediately before clearing, excavation, dewatering or waterway crossings.
  • Keep machinery stationary while the spotter catcher checks the work area, and require the operator to follow the spotter catcher's direction around water, vegetation and refuge features.
  • Do not pump, divert or discharge water from occupied or potential habitat without an approved method that protects fish, water quality and downstream connectivity.
  • Prevent the movement of aquatic weeds, fish, pathogens and contaminated water between sites by cleaning and drying equipment and using site-specific hygiene controls.

During habitat disturbance: Handling habitat and captured fish

  • Avoid disturbing aquatic vegetation, crayfish burrows, refuge pools, stream banks and connected flow paths unless the approved method specifically addresses them.
  • Do not remove logs, rocks, woody debris or riparian vegetation from retained habitat unless they obstruct an approved activity and the aquatic fauna ecologist has specified how they will be handled.
  • Use only trained and authorised personnel to capture, identify, hold or relocate Dwarf Galaxias, and follow the applicable permit, ethics and animal-welfare conditions.
  • Keep captured fish in clean, aerated water from the capture site for the shortest practical time, protect them from heat and direct sun, and do not mix fish from separate management units unless the approved translocation plan allows it.
  • Release fish only to nearby retained, suitable habitat identified in the fauna management plan and approved by the relevant authority; do not move them between catchments or management units without authorisation.
  • Take injured fish to an approved aquatic wildlife carer, veterinarian or other authorised facility, and record the outcome.

During habitat disturbance: Stop-work triggers and records

  • Stop work immediately if Dwarf Galaxias are found, if fish are stranded during dewatering, if occupied habitat is outside the approved footprint, or if sediment, chemicals or altered flows enter retained habitat.
  • Maintain the exclusion zone until the aquatic fauna ecologist or other authorised person has assessed the fish and confirmed the next action.
  • Stop work after an unexpected wetland connection, flood flow, fish kill, major sediment release or damage to a retained refuge feature, and notify the site environmental officer.
  • Record the date, time, location, number and life stage of each fish, capture and release details, habitat condition, water conditions, personnel, photographs, injuries, mortalities, incidents and corrective actions.
  • Notify the project manager, environmental regulator and relevant threatened-species authority when required by the approval or permit, and update the fauna management plan if the work method changes.

After habitat disturbance: Complete post-clearance checks

Post-clearance work must confirm that no fish or connected refuge habitat was missed and that retained habitat continues to function. Monitor both the works footprint and the connected waterways that support replenishment and dispersal. [Do not write source ids in text]

  • Inspect the full disturbance area, wetland margins, drains, creek edges, dewatering points and downstream connection after clearing and excavation.
  • Check for stranded, injured or dead fish in pools, sediment traps, excavations, pumps, culverts and isolated wet areas.
  • Remove temporary barriers only after the environmental officer confirms that retained habitat, water quality and surface-water connections are protected.
  • Repair damaged exclusion fencing, riparian vegetation, banks, crayfish burrows, aquatic vegetation and flow paths before the next work stage.
  • Verify that no spoil, sediment, concrete, fuel, herbicide or contaminated water remains in or can enter retained habitat.

After habitat disturbance: Monitor and report

  • Monitor retained and rehabilitated sites using repeatable methods, including the same survey locations, season, equipment and effort where practicable.
  • Monitor water levels, wetting and drying cycles, connectivity, aquatic and riparian vegetation, turbidity or other relevant water-quality observations, crayfish refuges and introduced fish.
  • Repeat targeted fish surveys where works altered habitat, hydrology or connectivity, and compare detections and recruitment with pre-work records.
  • Report captures, mortalities, habitat damage, incidents, corrective actions, survey results and database submissions to the approval authority and project records.
  • Maintain sediment, access, stock and weed controls until the environmental officer confirms that the site is stable and rehabilitation objectives are being met.

After habitat disturbance: Offsets and residual impacts

  • Reassess residual impacts after avoidance, mitigation and rehabilitation measures have been applied.
  • Obtain approval for any required offset, conservation agreement, habitat protection instrument or translocation before relying on it to address residual impacts.
  • Use offset or protection sites that maintain the species' genetic and management-unit diversity and protect connected shallow freshwater habitat, not isolated waterbodies alone.
  • Document the area, condition, tenure, management actions, monitoring period and responsible organisation for any offset or conservation site.

Rehabilitation actions: Rebuild wetland and riparian habitat

Rehabilitation should recreate functioning shallow freshwater habitat and the connected wetland network used by Dwarf Galaxias. A pond that holds water but lacks suitable vegetation, refuge habitat or connection to source populations may not support recovery. [Do not write source ids in text]

Typical habitat depth: About 0.5 to 1.5 m

Common habitat elevation: Typically 25 to 72 m above sea level

Vegetation examples: Rushes and sedges

  • Reinstate shallow, slow-flowing or still freshwater habitat with permanent, semi-permanent, seasonal and ephemeral components where appropriate to the local system.
  • Design wetland and drainage works to retain natural wetting and drying cycles and intermittent flooding connections to permanent creeks or rivers.
  • Re-establish dense native emergent and submerged vegetation, including locally appropriate rushes and sedges, along shallow margins and in refuge areas.
  • Restore native riparian vegetation to provide shade, litter input, bank stability and protection from sediment and nutrient runoff.
  • Avoid creating fast-flowing channels, concrete drains or simplified banks because the species prefers shallow, slow-flowing or swamp-like habitat.

Rehabilitation actions: Retain refuge features and control threats

  • Retain or reinstate suitable natural substrates, aquatic vegetation, woody debris and freshwater crayfish burrows where they form dry-season refuge habitat.
  • Do not introduce fish, crayfish or other aquatic animals to rehabilitation wetlands without a risk assessment and approval.
  • Control eastern gambusia, redfin perch, trout, goldfish, weatherloach, carp and other introduced species where they threaten the rehabilitated population and control is authorised.
  • Exclude stock from restored wetlands and riparian margins, provide off-stream watering where relevant, and protect banks from trampling.
  • Manage weeds and runoff so aquatic vegetation, water quality, dissolved oxygen and shallow refuge habitat are maintained.

Rehabilitation actions: Monitor success and manage fire risk

  • Monitor wetland depth, duration of inundation, drying, flood connection, aquatic and riparian vegetation cover, water quality, crayfish refuge features and introduced species.
  • Undertake repeat fish surveys in suitable seasons using standardised trapping, scoop-netting or electrofishing effort, and record presence, abundance, recruitment and mortality.
  • Treat detection of multiple life stages, repeated recruitment and persistence through expected drying periods as useful indicators of a self-sustaining population.
  • Manage fire planning to reduce ash and sediment runoff into wetlands and streams, and inspect waterways after fire and major rainfall for sediment slugs, water-quality changes and fish mortality.
  • Continue monitoring until the responsible ecologist and approval authority agree that habitat condition, connectivity and fish population measures meet the approved rehabilitation objectives.

Sources