Description: This active shoaling fish inhabits the aquarium’s middle waters and is a peaceful addition to a community aquarium (although it may nip at slow fish with long, flowing fins). The red-eye tetra has a mostly silver body, but its back displays green iridescent scales with dark edgings. This species has a black vertical band on the base of the forked caudal fin and a thinner yellow band on the caudal peduncle (giving it its other common name of yellow-banded tetra). Moenkhausia sanctaefilomenae has mostly clear fins, but the fronts of the pelvic and anal fins are edged in white. This fish gets its common name of red-eye tetra from the arc of bright red color on the top half of the eye.
Keep a group of six or more red-eye tetras in a spacious aquarium (at least 20 gallons for a small shoal) that has plenty of swimming room. Moenkhausia sanctaefilomenae nibbles on soft plants, so provide hiding areas with plastic plants or hardy, tough-leaved plants that can withstand their nibbling. Also keep a dark substrate to help their silver bodies stand out in the aquarium.
Red-eye tetras are omnivorous and should be fed high-quality fish flakes as the staple diet. Occasionally feed your red-eye tetra shoal live foods, as well as plant matter (use a vegetable clip to offer Romaine lettuce in the aquarium). With regular partial water changes and good diet, your red-eye tetras can live for five years or more.
Breeding: Female red-eye tetras have much rounder bellies when filled with roe. Breeding aquariums should be heavily planted or have spawning mops so the parents do not eat the eggs. They scatter several hundred eggs among the plants, even among roots of floating plants. Remove the parents from the breeding aquarium after they have spawned so that they do not eat the eggs. The eggs hatch in two days, and the red-eye tetra fry will hang on plants or on the aquarium glass for a few days. At this point, feed liquid foods for fry. When they are about a week old, they can take newly hatched brine shrimp and then be weaned onto finely crushed flake foods.