Max Size: 6cm

Red Laser Tetra (Hemigrammus coeruleus)

Red Laser Tetras can be pretty difficult to find. As a result, these Tetras are rare and are a highly sought after species of Tetra. These fish are one of the larger sized Tetras available in the aquarium hobby. The Red Laser Tetras friendly and active disposition and ease of care make them ideal members of a community aquarium.

Red Laser Tetras are a schooling species in nature; therefore, you should keep them in a group of at least six individuals, preferably more. Keeping these fish in more significant numbers will not only make your aquarium look more effective, but the fish will also fare much better when kept with its own kind.

Ideal tankmates for these tetras would be Danios, Rasboras, other Tetras, Pencilfish and Livebearers, as well as peaceful bottom-dwelling species such as Corydoras Catfish or smaller Loricariids. You can also keep Red Lazer Tetras with Gouramis and Dwarf Cichlids. However, it would be better to avoid aggressive or much larger species such as Angelfish as they may see these Tetras as a snack.

The best aquarium setup for the Red Lazer Tetras would be a biotope setup using river sand as a substrate and adding a few driftwood branches and twisted roots. In addition, adding some dried beech or oak leaves would complete the natural feel. It would be beneficial for your fish if you allowed the wood and leaves to stain the water a brown colour, removing decaying leaves and replacing them every few weeks, so they do not rot and foul the water. Red Lazer Tetras will also appreciate some cover from aquatic plants.

Both male and female Red Laser Tetras have transparent bodies that display a neon pink line down their sides. In addition, all their fins are transparent except for the anal and pelvic fins that are clear with white tips. However, when these fish are in spawning condition, the male's bodies will become a deep ruby red, and their fins get really dark, so much so that you could mistake them for an entirely different species altogether.

Quick Facts
Scientific NameHemigrammus coeruleus
Other NamesWatermelon Tetra, Coreulean Pink Tetra
Aquarium LevelMiddle - Top
DifficultyBeginner - Intermediate
Best kept asGroups 6+
Lifespan2 - 4 years
Water Parameters
Water TypeFreshwater
PH5.5 - 7.5
GH2 - 15
75 - 82℉
23.9 - 27.8℃


Red Laser Tetra

Natural Habitat

Again there is little information available on the natural habitat of these fish; however, they are believed to originate from the lower Rio Negro River Basin in Peru in South America. Their native habitat contains sandy and silt substrate, bogwood branches and some vegetation. These fish come from soft tannin-stained water areas that are covered with shade.


Red Laser Tetras will readily accept good quality dried food such as micro pellets and crushed flakes alongside live, frozen and freeze-dried food such as mosquito larvae, brine shrimp and daphnia. However, these Tetras will not eat any food that falls to the bottom of the aquarium; therefore, you must make sure you do not overfeed them; otherwise, the water may become polluted.

Sexual Dimorphism

It is somewhat challenging to distinguish between male and female Red Laser Tetras as they look very similar. However, when they start spawning, everything changes, and the difference becomes apparent. The female will become noticeably larger as she is full of eggs, but the most fascinating change is the fact that the male transforms into a completely different looking fish. His entire body becomes bright red, and his fins turn a dark, almost black colour.


Unfortunately, there is very little to no information available on how to breed the Red Laser Tetras. However, they more than likely breed in a similar fashion to other Hemigrammus species.

Red Laser Tetras will require a separate breeding tank with very soft, warm water and dim lighting; the tank will need to be heavily planted with fine-leaved plants such as java moss, spawning mops can also be used and works well.

It would be better if you conditioned your fish with plenty of live and frozen foods as this encourages them to spawn.

You will recognise when a female is ready to spawn as she will become very plump. At this point, you should put your best-coloured male and the biggest female into the breeding tank. Whenever the pair is ready to spawn, the male will vigorously swim around the tank after the female, performing a courting display where he flicks his fins and shimmies near the female. Finally, the female will discharge her eggs, and then the male will fertilise them.

A typical spawning will usually consist of around 100 to 150 eggs. However, The parents will not provide any parental care and will consume the eggs if given the opportunity, so make sure you remove them as soon as spawning has finished. In addition, the eggs are susceptible to light, so it is advisable that you keep the breeding tank in darkness.

Hatching usually occurs 24 to 36 hours later, and the fry will become free-swimming a couple of days after that.

It would be best to initially feed the fry with infusoria or paramecium and then move on to finely crushed flake food. After several days, you can provide them with newly hatched baby brine shrimp and micro worms to help them develop.

Other Tetras of interest

African Moon Tetra(Bathyaethiops caudomaculatus)
African Red Eyed Tetra(Arnoldichthys spilopterus)
Black Darter Tetra(Poecilocharax weitzmani)
Black Line Tetra(Hyphessobrycon scholzei)
Black Neon Tetra(Hyphessobrycon herbertaxelrodi)
Black Phantom Tetra(Hyphessobrycon megalopterus)
View all Tetras
Date Added: 10/09/2021 14:58:14 - Updated: 02/12/2021 17:35:18