Rainbow Tetra (Nematobrycon Lacortei) Fish Species Profile

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The Rainbow Tetra is uncommon and rare in the hobby, but they are a beautiful, hardy, and a peaceful shoaling species. Still, they can be somewhat territorial and may bully other fish. Yet, as long as you have a group of 8 or more they can happily be kept with other species in the community aquarium.

This fish is iridescent and display every colour of the Rainbow on its club-shaped body and also has a dark line that extends from the eye to the caudal fin. It also has a trident tailed caudal fin with a centre spike and elongated anal fins that extend from the vent of the fish to the caudal fin. The Rainbow Tetra also has large eyes that are banded with red.

Scientific NameNematobrycon Lacortei
OriginsSouth America
Aquarium LevelMiddle
DifficultyBeginner - Intermediate
Best kept asGroups 8+
Lifespan3 - 5 years
Maximum Sizeup to 4 cm
Water Conditions
Water TypeFreshwater
Temperature72 - 80 ℉ (22.2 - 26.7 ℃)
PH5.0 - 7.0
GH5 - 8

Origins of the Rainbow Tetra

The Rainbow Tetra is endemic to Rio Calima in the Rio San Juan River system, which drains the sections of Choco and Valle de Cauca in western Colombia in South America.

They inhabit small, sluggish, isolated tributaries that are heavily vegetated.


Rainbow Tetras are not fussy when it comes to their food. Feed them high-quality flakes, granules and micropellets and supplement that with vitamin-enriched live and frozen foods such as bloodworms artemia, daphnia, and mosquito larvae.

Remember these fish are very small so they will be unable to consume a lot of food.

Sexing the Rainbow Tetra

It is effortless to determine the male species from the females.

Adult males have more-extended anal, dorsal and caudal fins are much more colourful, and they possess red eyes, whereas the females have green-blue eyes and are much more full-bodied than the males mostly when ready to spawn.

Breeding the Rainbow Tetra

The Rainbow Tetra, when paired off, will breed with little to no help necessary.

To successfully receive the most amount of fry you will need to condition the pair with high quality frozen or live food for a couple of weeks before spawning and to provide them with their own breeding tank, this should be dimly lit and have soft acidic water. You will need to place a spawning mop or some dense floating plants for them to place their eggs, alternatively; you could put some mesh on the bottom of the tank that will be large enough for the eggs to fall into but small enough so that the adults can not get to the eggs.

Rainbow tetras will only release a few eggs at a time so the process could take several hours. As soon as you start noticing eggs, it is advisable to remove the adults to avoid them consuming their spawn.

If you are unable to see any eggs after a couple of days, this means it has been unsuccessful therefore you will have to remove them and try again with a different pair.

The eggs will typically hatch within 24-36 hours. You will need to feed them infusoria-grade food for the first week or so, after hatching they should become free swimming 4-5 days later.

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Date Added: 9/9/2020 - Updated: 9/9/2020 4:17:52 PM