Corydoras julii (also known as the julii cory or leopard catfish[1]) is a small freshwater catfish native to eastern Brazil. It is often confused with Corydoras trilineatus,[2] the three stripe corydoras. Corydoras julii are small, peaceful shoaling fish, and are typically kept in groups in captivity.
Corydoras julii is a relatively small species of fish, growing to be no more than 52 millimeters in length.[3] Its skin is a translucent whitish-gray, with fine black spotting across the body and a horizontal stripe which reaches up the mid-body until it is equal with the front base of the dorsal fin. This spotting pattern is the primary visual difference between C. julii and three stripe corydoras (C. trilineatus), which have larger reticulations, as opposed to spots, and a longer mid-body stripe. C. julii might be further distinguished from C. trilineatus by the spotted pattern on its head; however, C. trilineatus can also show this pattern on occasion. Females are typically larger and rounder than males.[4]
Corydoras julii, like almost all Corydoras species, are bottom-feeding scavengers. Their diet consists primarily of small invertebrates which they sift from the substrate, expelling the particles of sand and sediment through their gill openings.
In captivity, their diet is frequently sinking pellets rich in insect and other invertebrate proteins, as well as live or frozen invertebrates like bloodworms, daphnia, brine shrimp, and California blackworms (Lumbriculus variegatus).[5]
After sexual maturity, Corydoras spawning appears to be triggered by storms. During this storm, the fish eat increased amounts of insects. The water gradually decreases temperature over the course of a few days.
Corydoras fish breed in a position resembling a "T formation". In this formation, the female swims up to the male's abdomen, and consumes sperm released by the male. The sperm rapidly travels though the female's intestinal tract and fertilizes the eggs in the cloaca. Small, white, sturdy eggs are laid on plant leaves in the wild. Adult corydoras have been known to eat their own eggs.