Red-eyed tetras (Moenkhausia sanctaefilomenae) are so named because the upper half of their eye is bright red. They are from South America and belong to the family Characidae, which includes neon and cardinal tetras. The red-eyed tetra looks very similar to the glass tetra (Moenkhausia oligolepsis) but red-eyed tetras are smaller and more colorful. Red-eyed tetras are sometimes referred to as yellow-banded tetras because of the yellow band next to the black band by the tail.
They reach a size of about 2.7 inches or 7 centimeters in length. They prefer slightly acidic water (pH of about 6.8) and a water temperature of between 75-79 degrees Fahrenheit or 24-26 degrees Celsius.
They are peaceful fish that do well in community tanks with other peaceful fish. You should keep at least 4-6 red-eyed tetras together because they are shoaling fish. They do best in aquariums that are well planted, but with plenty of swimming room. They generally swim at midlevel.
They are omnivorous (both meaty foods and plant based foods). They readily eat flakes, frozen, freeze-dried, and live foods.
They are egglaying fish and are easy to breed in the aquarium. During spawning they scatter their eggs, which hatch about 24-28 hours later. After spawning is complete it is best to remove the parents so they don't eat the fry when the hatch.
When the fry become free-swimming they should be fed liquid fry food for egg laying fish and newly hatched brine shrimp when they are able to eat them.