AquaNexus verified profile
Turquoise rainbowfish
Melanotaenia lacustris
Turquoise rainbowfish is Melanotaenia lacustris, a Lake Kutubu endemic requiring a group of eight to twelve, long swimming space and stable mineral-rich alkaline water.
Outcome: PASSED Permanent ID: 703
Profile overview
- Scientific Name
- Melanotaenia lacustris
- Identity and search names
- Turquoise rainbowfish, Lake Kutubu rainbowfish, Melanotaenia lacustris
- Category
- Freshwater fish
- Subgroup
- Rainbowfish and blue-eyes
- Environment
- Freshwater aquarium
- Origin
- Lake Kutubu and the connected Soro River system in Papua New Guinea
- Care
- Beginner
- Adult Size
- About 10–12 cm total length
- Lifespan
- 5–8 years
- Tank
- At least 250 L for eight to twelve in a long aquarium
- Temp
- 20–25 °C
- pH
- 7.2–8.2
- Hardness
- Moderately hard to hard, mineral-rich water; avoid very soft acidic conditions
- Salinity
- Freshwater; no routine salt addition
- Lighting
- Normal aquarium lighting
- Placement
- Mid and upper water
- Diet
- Omnivore taking insects, crustaceans, algae and other available foods
- Filtration
- Use mature biological filtration with effective mechanical solids capture and turnover matched to the species’ natural flow needs. Protect intakes, preserve established media during cleaning and keep ammonia and nitrite at zero.
- Aeration
- Maintain continuous surface agitation and dependable dissolved oxygen across the whole aquarium. Increase oxygen reserve in warm water, strong-current systems, dense groups, medication periods and power interruptions.
- Maintenance
- Observe feeding, respiration, body condition and social behaviour daily; test nitrogen waste and key chemistry on a schedule; clean mechanical media before trapped waste decomposes; and perform regular temperature- and chemistry-matched water changes.
- Welfare
- Maintain the stated adult space and social structure, verify feeding, and intervene early when injury, exclusion, weight loss, abnormal respiration or altered behaviour appears. Melanotaenia lacustris is a restricted Lake Kutubu endemic. Keep location and strain records, avoid rainbowfish hybridisation and do not maintain it in soft acidic water merely because other rainbowfish tolerate it.
- Biosecurity
- Never release fish, fry, eggs, aquarium water, sediment, plants or live foods into drains, dams or natural waterways. Confirm current Australian import conditions and South Australian possession, trade and movement rules before acquisition or transfer.
- Review Status
- PASSED
- Source Status
- CURRENT — accepted identity or explicitly bounded species profile; husbandry, welfare, sources and Australian/South Australian biosecurity rechecked. CURRENT
App-ready care, welfare and biosecurity details
Identity Scope
Single-species profile for Melanotaenia lacustris. Preserve permanent AquaNexus ID 703, slug turquoise-rainbowfish and route /species/turquoise-rainbowfish/; retain former combinations, locality labels and trade names only as searchable aliases.
Adult Size And Space
Expected adult size: About 10–12 cm total length. Minimum permanent housing: At least 250 L for eight to twelve in a long aquarium. Plan around adult dimensions, activity, social structure, aggression, oxygen demand and waste production rather than sale size.
Social Structure
Keep eight to twelve with multiple males and females; large groups support normal display without one fish carrying all social pressure
Swimming Zone
Primary zone: Mid and upper water. Keep that zone usable for movement, feeding, refuge and escape.
Feeding Ecology
Omnivore taking insects, crustaceans, algae and other available foods
Feeding Plan
Offer quality prepared foods plus small live or frozen prey and plant-rich items once or twice daily
Water Stability
Maintain 20–25 °C; pH 7.2–8.2; hardness or minerals: Moderately hard to hard, mineral-rich water; avoid very soft acidic conditions; salinity: Freshwater; no routine salt addition. Stable oxygenation and nitrogen-cycle control matter more than chasing one exact value.
Habitat Structure
Long covered aquarium with open midwater swimming room, planted margins, moderate flow, strong oxygenation and stable mineral-rich alkaline water
Compatibility Plan
Use similarly active peaceful fish that tolerate the same mineral-rich water; avoid fin nippers and slow feeders
Breeding Plan
Plant or mop spawner producing adhesive eggs over an extended period Parental care: No parental care; adults may eat eggs and fry.
Quarantine
Quarantine new fish in a separate cycled aquarium with dedicated equipment. Match temperature and mineral chemistry gradually, confirm feeding, respiration, skin, fins and waste, and never add transport water to the established aquarium.
Welfare Checks
Maintain the stated adult space and social structure, verify feeding, and intervene early when injury, exclusion, weight loss, abnormal respiration or altered behaviour appears. Melanotaenia lacustris is a restricted Lake Kutubu endemic. Keep location and strain records, avoid rainbowfish hybridisation and do not maintain it in soft acidic water merely because other rainbowfish tolerate it.
Biosecurity And Release
Never release fish, fry, eggs, aquarium water, sediment, plants or live foods into drains, dams or natural waterways. Confirm current Australian import conditions and South Australian possession, trade and movement rules before acquisition or transfer.
Main Risk
Melanotaenia lacustris is a restricted Lake Kutubu endemic. Keep location and strain records, avoid rainbowfish hybridisation and do not maintain it in soft acidic water merely because other rainbowfish tolerate it.
Adult Projected Load
Plan filtration and stocking for the full adult size (About 10–12 cm total length), the complete social group and peak feeding waste, not the current shop size. Permanent housing remains At least 250 L for eight to twelve in a long aquarium.
Filtration
Use mature biological filtration with effective mechanical solids capture and turnover matched to the species’ natural flow needs. Protect intakes, preserve established media during cleaning and keep ammonia and nitrite at zero.
Aeration
Maintain continuous surface agitation and dependable dissolved oxygen across the whole aquarium. Increase oxygen reserve in warm water, strong-current systems, dense groups, medication periods and power interruptions.
Maintenance
Observe feeding, respiration, body condition and social behaviour daily; test nitrogen waste and key chemistry on a schedule; clean mechanical media before trapped waste decomposes; and perform regular temperature- and chemistry-matched water changes.
Overridable Warnings
Warnings are decision support, not permission to ignore welfare limits. Override only with specimen-specific evidence, equivalent risk controls and a recorded reason; never override legal, biosecurity, provenance or no-release requirements.
Sources and review basis
- Eschmeyer’s Catalog of Fishes — Melanotaenia lacustris: Taxonomy — accepted name, former combinations, synonyms and identity cross-check
- ANGFA — Melanotaenia lacustris species account: Distribution, water chemistry and husbandry — Lake Kutubu endemic identity and mineral-rich habitat
- IUCN Red List search — Melanotaenia lacustris: Conservation and provenance — wild status, locality and collection-risk cross-check
- PIRSA — South Australian noxious fish list: Australian biosecurity — current South Australian possession, trade and movement restrictions
- DAFF — importing live ornamental fish to Australia: Australian biosecurity — national live-fish import pathways and permitted-species warning
AquaNexus uses original editorial synthesis. Exact import, possession, movement and disposal requirements must be rechecked with the current authority before acquisition or transfer.