Redeye Tetra Fish Species Profile

Characteristics, Origin, and Helpful Information for Hobbyists

Red Eye Tetra - Moenkhausia sanctaefilomenae

Indy Poon / Flickr / CC BY-NC 2.0

The redeye tetra adds a touch of glamour to a freshwater community aquarium. Their metallic look, dynamic energy, and signature red eye with its pop of color combine to create an elegant display when kept in a school of six or more. This fish is also a good choice as a beginner fish. Water conditions fluctuate wildly in its natural habitat, so this fish can tolerate a wide range of differences and changes. The redeye tetra is a relatively larger tetra and should ideally be housed in a 20-gallon or larger aquarium.

Species Overview

Common Names: Yellow-banded moenkhausia, yellowback moenkhausia, yellowhead tetra, lamp eye tetra

Scientific Name: Moenkhausia sanctaefilomenae

Adult Size: 2.75 inches

Life Expectancy: 5 years

Characteristics

Family Characidae
Origin Bolivia, Brazil, Paraguay, Peru
Social Peaceful
Tank Level Mid-dweller
Minimum Tank Size 20 gallon
Diet Omnivore
Breeding Egglayer
Care Easy
pH 5.5 to 8.5
Hardness Up to 25 dGH
Temperature 73 to 82 F (23 to 28 C)

Origin and Distribution

Redeye tetras are found in South America in Paraguay, eastern Bolivia, eastern Peru, and western Brazil. In the wild, they inhabit clear rivers but can sometimes be found living in the thick vegetation of the murky Amazon. Aquarium specimens are now bred extensively in Asia.

Colors and Markings

If you have ever seen a school of these tetras with their bright silver body accented by a black tail and red eyes, it is obvious how they got their name. This peaceful medium-sized tetra is readily available and suitable for most community aquariums. 

Tankmates

Redeye tetras are very peaceful; they are best kept in schools of six or more and will claim the mid-portion of the aquarium. Although they are easygoing, some owners report that they occasionally nip at the fins of slow-moving, long-finned fish. Redeye tetras are very active in the middle section of the tank and may disturb less active top-dwelling fish. In addition, other tetras may pick on them at times, so keep an eye on the community.

These tetras do well in a community tank. Good tankmates are other tetras, rainbowfish, barbs, danios and the larger rasboras. Most peaceful bottom dwellers will also make good tankmates.

Habitat and Care

Redeye tetras tolerate a range of water conditions, from hard alkaline to soft acidic water. In nature, these fish come from regions with dense forests that let little light through, so keep their tank dimly lit; use dark substrate and plant cover along the sides and back of the aquarium.

These fish do not prefer fast-moving currents, so make sure to angle the filters to avoid disturbing them. Their ideal aquarium includes live plants, driftwood, and rocks to recreate their natural habitat and offer spaces to hide. Since this is a relatively large tetra, they require a 20-gallon tank or larger. For these tetras, at least 25 to 50 percent of the water should be replaced every other week.

Redeye Tetra Diet and Feeding

Redeye tetras are omnivores, meaning they will eat a variety of foods. In the wild, they feed on worms, crustaceans, and insects. In captivity, you can feed them fine flake food, small granules, live or frozen brine shrimp, daphnia, tubifex, and frozen or freeze-dried bloodworms. Offer a variety of food, including live foods, to ensure good health. 

Vegetables should be offered regularly to bring out their best colors and appearance. Spinach is a great choice for this fish. This tetra prefers to eat multiple times a day. Offer only what they can consume in three minutes or less with multiple feedings per day.

Gender Differences

Sexual differences are not overtly apparent in most tetras. Generally, the female will have a larger more rounded abdomen than the male. A female's belly fills with eggs when it is sexually mature. Males get very colorful when ready to mate. Select the brightly colored males for breeding.

Breeding the Redeye Tetra

When attempting to breed redeye tetras, set up a separate breeding tank with a slightly acidic pH (5.5 to 6.5), and very soft water (4 dGH or below). A 20-gallon spawning tank is fine, with a temperature of 80 to 84 F (26.6 to 29.0 C).

Keep the tank dimly lit with clumps of spawning mops or Java moss. A layer of mesh also works as long as the spaces are wide enough for the eggs to pass through and small enough to keep the parents out. A small, air-powered sponge filter is needed for filtration and will provide gentle water flow. Filtering the spawning tank water through aquarium-safe peat is a good choice as well.

Redeye tetras can be spawned in pairs, but for best success, spawn them in groups of about 12 individuals, with half a dozen each of males and females. Prior to breeding, condition the males and females in separate tanks. Feed them plenty of small live foods for about seven to 10 days. Select a breeding pair or small group and transfer them into the breeding tank in the evening. They should spawn the following morning. 

If you provide floating plants, the breeding pair will often lay eggs among them. When they spawn, they lock fins, and then while clasped, they perform a type of roll-over process in the vegetation. The female releases about a dozen eggs at a time and the male fertilizes them. Because of this spawning behavior, the redeye tetra must not have too dense a spawning vegetation.

Once spawning has occurred, remove the mating pair, as they will consume both the eggs and hatching fry. The eggs will hatch one to two days after they are laid. Initially, feed the fry commercially prepared fry foods; then offer freshly hatched brine shrimp, and eventually finely crushed flake foods.

More Pet Fish Breeds and Further Research

If redeye tetras appeal to you, and if you are interested in some compatible fish for your aquarium, read up on:

Check out additional fish species profiles for more information on other freshwater fish.