Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Moenkhausia sanctaefilomenae

Red eyed tetra

Red eyed tetra, Moenkhausia sanctaefilomenaeRed eyed tetra, Moenkhausia sanctaefilomenae
Photos by Andy Rapson


General Notes:

An excellent fish for the beginner, red eyed tetras are peaceful, undemanding and very hardy. They are slightly larger than most community tetras and so they require a little more space in order to behave more naturally due to their lively boisterous nature. Red eyed tetras are a shoaling species and it is far better to keep them in a group of at least five individuals. When keeping shoaling fish it is better to keep an odd number rather than an even number simply because they look better that way.


Wild red eyed tetras feed on worms, insects, crustaceans and plant matter. In captivity they will accept all suitably sized food. Use a good quality flake food and supplement this with live or frozen blood worms, daphnia, brine shrimps ect.


Adult females are larger and have more rounded abdomens than the adult males


Use soft, slightly acidic aged water as follows. Use a separate aquarium filled with soft acidic aged water and containing a small air powered sponge filter and something to act as a spawning mop such as a bunch of fine leaved plants tied in to a bunch for example. Keep the tank away from direct light and in very dim conditions because both eggs and fry of this species are light sensitive. Introduce a well conditioned pair in the evening and they will probably spawn at dawn. After spawning remove the parents to prevent them from eating all their eggs. The eggs hatch after about 30 hours but it will be another three or four days before the fry become free swimming. Add a commercially available liquid fry food to the tank about a day or so before the fry become free swimming as this will encourage the growth of infusoria which the fry can eat but don't add to much and pollute the water. Carry on using the liquid food or similar until the fry are large enough to take micro worms or newly hatched brine shrimps. Red eyed tetras can be bred as a pair or in a group. If you breed them in a group be aware that you will have a very large number of fry which will require a great deal of space to raise and dealers won't thank you if you flood the local market with these fish and they end up stuck with them.

Wild status

The health of wild populations of red eyed tetras has not been evaluated, all specimens of this species offered for sale will have been commercially bred and not taken from the wild.

Information at a glance

pH: 6 - 7.2
dGH: 4 - 15
Temperature: 22 - 26°C (72 - 78°F)
Diet: Omnivore
Size: 7cm (2.7in)
Min tank size: 100 litres
Difficulty level: Easy
Aquarium type: Community
Swimming level: All levels

Distribution and habitat

distribution map for Red eyed tetra, Moenkhausia sanctaefilomenae

Origin: South America: Paranaíba, São Francisco, upper Parana, Paraguay and Uruguay River basins

Habitat: heavily vegetated clear water.


Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Characidae
Genus: Moenkhausia
Species: M. sanctaefilomenae

Common name:
Red eyed tetra

Synonyms: Tetragonopterus sanctaefilomenae, Moenkhausia australe