A rare and beautiful rainbowfish native to slow-flowing, shaded rainforest streams in New Guinea. They thrive in unusually warm, alkaline waters compared to some other rainbowfish. As active, schooling fish, they require plenty of swimming space alongside dense planting and floating plants to mimic their natural shadowed habitat.
Lorentz's Rainbowfish At a Glance
Lorentz's Rainbowfish Tank Requirements
Will Lorentz's Rainbowfish fit in your tank?
Care guides tell you what Lorentz's Rainbowfish needs, the next question is whether your tank can safely provide it. Test Lorentz's Rainbowfish against your tank size, maintenance needs, and the fish you already keep before you buy.
Useful setup supplies
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Lorentz's Rainbowfish Water Parameters
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Lorentz's Rainbowfish Temperament & Compatibility
Lorentz's Rainbowfish Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Male
Males develop a slightly deeper body and display more intense coloration, featuring a distinct broad blackish mid-lateral stripe against a bluish or silvery side. They are highly active and will display continuously to females.
Differs in 2 traits from base species
Also known as: Standard, Male Rainbowfish
Female
Females are slightly smaller, more streamlined, and exhibit subdued silvery or olive coloration without the prominent black lateral stripe. Keeping a higher ratio of females to males helps disperse male chasing behavior.
Differs in 1 trait from base species
Also known as: Female Rainbowfish
Lorentz's Rainbowfish Care Guide Summary
The Lorentz's Rainbowfish, scientifically known as Chilatherina lorentzii, belongs to the Rainbowfish family group. Adults reach a maximum size of approximately 10 cm and have a fusiform body shape with a moderate growth rate. Classified as peaceful, this species primarily occupies the surface and mid-level zones of the aquarium and produces a low level of biological waste.
To thrive, the Lorentz's Rainbowfish requires a freshwater only aquarium with a minimum volume of 150 litres and a tank length of at least 90 cm. Water temperature should be maintained between 26°C and 30°C, with a pH range of 7.2–8 and a general hardness of 8–15 dGH. A low water flow is preferred.
Due to its specialist needs, the Lorentz's Rainbowfish is best suited for fishkeepers who can provide a carefully planned setup. This species is available in 2 varieties: Male and Female. Each may differ slightly in size, temperament, or care needs, so it is worth checking the specific requirements of the variety you plan to keep.
Lorentz's Rainbowfish Habitat Setup
When setting up an aquarium for the Lorentz's Rainbowfish, a low water flow best suits their natural preferences. Because this species occupies the surface and mid-level zones, the aquarium layout should prioritise adequate surface area with floating cover to make them feel secure near the waterline and open swimming space in the centre of the tank for free movement. Useful additions include driftwood, which can serve as both a hiding place and a dietary supplement, leaf litter or blackwater tannins to replicate their natural soft-water habitat, dense planting to provide cover, break sightlines, and reduce stress, and floating plants to diffuse overhead light and create shaded areas. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.
Lorentz's Rainbowfish Compatibility Notes
Classified as peaceful, the Lorentz's Rainbowfish is a schooling species that feels most secure in a sizeable group, where natural shoaling behaviour reduces stress and brings out their best colours. When choosing tankmates, shy or slow-feeding tankmates may be outcompeted at feeding time and their energetic swimming style may stress more sedentary or timid species. Selecting tankmates that favour different water layers from the surface and mid-level zones can help reduce competition and territorial overlap.
Lorentz's Rainbowfish Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Lorentz's Rainbowfish.
40 Gallon Breeder
55 Gallon Standard
60 Gallon Breeder
75 Gallon Standard
90 Gallon Standard
125 Gallon Standard
Show 9 more tank sizes
Lorentz's Rainbowfish Feeding & Diet Considerations
The Lorentz's Rainbowfish will eat fry, so breeding efforts in the same tank are unlikely to succeed and is an aggressive eater that may prevent timid tankmates from getting enough food, so target feeding or simultaneous feeding at opposite ends of the tank can help.
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Frequently Asked Questions About Lorentz's Rainbowfish
How big does Lorentz's Rainbowfish get?
Lorentz's Rainbowfish (Chilatherina lorentzii) typically reaches a maximum adult size of approximately 10 cm. They have a fusiform body shape and a moderate growth rate.
What tank size does Lorentz's Rainbowfish need?
A minimum aquarium volume of 150 litres and a tank length of at least 90 cm are recommended for Lorentz's Rainbowfish. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Lorentz's Rainbowfish need?
Lorentz's Rainbowfish thrives in freshwater only conditions with a temperature range of 26–30°C, a pH between 7.2 and 8, and a general hardness of 8–15 dGH. A low water flow is preferred.
Is Lorentz's Rainbowfish peaceful or aggressive?
Lorentz's Rainbowfish is classified as peaceful with an aggression score of 2 out of 10. They are generally well-suited to peaceful community tanks.
How many Lorentz's Rainbowfish should be kept together?
Lorentz's Rainbowfish is a schooling species and should be kept in groups of at least 6. Larger groups help distribute aggression and encourage natural schooling behaviour.
Does Lorentz's Rainbowfish have any special tank requirements?
Yes. Lorentz's Rainbowfish benefits from plants - densely covered, plants - floating, driftwood (digestion/hiding), and leaf litter/blackwater in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Does Lorentz's Rainbowfish need a lid on the tank?
Yes. Lorentz's Rainbowfish is a known jumper, and a tight-fitting lid or cover is essential to prevent escape. Even a small gap can be enough for a determined fish to leap out.
Top Tank Mates for Lorentz's Rainbowfish
These fish are strong compatibility matches for Lorentz's Rainbowfish based on water preferences, temperament, adult size, and tank behavior.
Emerald Green Cory
Corydoras splendens
Ideal Tank MatesMalaysian Trumpet Snail (MTS)
Melanoides tuberculata
Ideal Tank MatesGhost Shrimp
Palaemonetes paludosus
Ideal Tank MatesAssassin Snail
Anentome helena
Ideal Tank MatesOrange Chromide
Etroplus maculatus
Ideal Tank MatesMalaya Shrimp
Caridina sp. "Malaya"
Ideal Tank MatesPlants That Suit Lorentz's Rainbowfish
These plants pair well with Lorentz's Rainbowfish based on shared water preferences, layout fit, and how likely they are to hold up in the same aquarium.
Amazon Frogbit
Limnobium laevigatum
Asian Watergrass
Hygroryza aristata
Asian Watermoss
Salvinia cucullata
Carolina Mosquito Fern
Azolla caroliniana
Common Duckweed
Lemna minor
Crystalwort
Riccia fluitans
Fish Similar to Lorentz's Rainbowfish
New Guinea Rainbowfish
Melanotaenia affinis
An active, schooling species native to the streams of northern New Guinea. Known for their striking lateral stripe and vibrant fin coloration that flashes during morning displays. They are peaceful but highly energetic, requiring ample open swimming space and highly oxygenated water to thrive.
Ogilby's Rainbowfish
Melanotaenia ogilbyi
A rare and stunning schooling fish endemic to the Lorentz River system in West Papua. Belonging to the 'maccullochi' species group, they are relatively small for rainbowfish. They feature a distinct dark mid-lateral stripe and striking horizontal red/orange stripes between their scales. They are incredibly active, peaceful, and thrive in groups where males will 'flash' vibrant colors during morning spawning displays.
Bulolo Rainbowfish
Chilatherina bulolo
A rare and highly active rainbowfish native to the fast-flowing mountain streams and white-water rapids of the Markham and Ramu river systems in Papua New Guinea. They possess a silvery body with a distinct black streak on the upper and lower edges of the caudal fin. Because of their specialized natural habitat, they require highly oxygenated, fast-flowing water and alkaline conditions to thrive in an aquarium.
Sepik Rainbowfish
Glossolepis multisquamata
The Sepik Rainbowfish, also known as the Rosy Rainbowfish, is a vibrant schooling fish native to the floodplains, swampy lagoons, and slow-moving rivers of New Guinea. They are highly active swimmers that display stunning metallic and red coloration. They thrive in densely planted aquariums with ample open swimming space and require a group to feel secure and display their best colors.
Goldie River Rainbowfish
Melanotaenia goldiei
The Goldie River Rainbowfish is a vibrant, highly active schooling fish native to the clear rainforest streams and backwaters of southern New Guinea. As rapid swimmers, they require significant open swimming space. They are voracious mid-water and surface feeders that will readily eat insects and standard aquarium foods. While peaceful, their exuberant energy can intimidate shy tank mates.
Highlands Rainbowfish
Chilatherina campsi
A rare and elegant species endemic to the central highlands of Papua New Guinea. Unlike many tropical rainbowfish, it thrives in slightly cooler, well-oxygenated water. They are very active, peaceful schooling fish characterized by an olive/mauve back, silvery reflections, and a distinct blackish-to-blue mid-lateral stripe.