julii cory care guide

Julii cory (Corydoras julii), is a typical representative of this fish kind. It is a peaceful, schooling, and omnivorous freshwater fish. This article will tell you about fish in detail – where the fish dwells, whether it is a difficult fish to keep, how to create proper tank conditions to the fish, how to select tank mates and how to breed the fish.

Habitat in the wild

Julii corydoras habitat is in North-East Brazil. The fish is endemic to coastal river systems to the South of the Amazon River estuary in the state of Piauí, Maranhão, Para, and Amapa. The fish was found in the Guama River (including its tributaries such as The Ararandeua River), Maracanã, Morcego, Parnaiba, Piriá, Kaete, Turiaçu and Mearim River. Julii cory is encountered in small rivers, tributaries, and other water basins in a rainforest.

The fish got its name from someone whose personality is actually unknown. Corydoras julii is often confused with another catfish, because the fish appearance is quite similar to another kind – Corydoras trilineatus. This fish kind dwells on the upper course of the Amazon River, and it is less demanding.

Since it is rather popular and demanded fish, even those who are selling them can’t say for sure what kind of fish they are selling. Nevertheless, it is possible to see between these two fish kinds.

Julii cory has one clear stipe on the side of its body, while C. trilineatus has several stripes, and they are brighter and more pronounced. There are more differences, but only a specialist can see them.

Scientific NameCorydoras julii
Common NamesJulii cory; corydoras julii; julii catfish
Ease of keepingEasy
Lifespan7 years and more
Tank size30 gallons and more
Tank typeCommunity of fishes
DietOmnivorous bottom feeder
Temperature72-78 °F (22-26 °C)
Water hardness2–20 dGH
Sizeup to 3 in (7.5 cm)


It is one of the most appealing Corydoras species due to its bright coloring. The fish body is white-gray close to ivory white with small back spots and undulated lines scattered over it.

Along the lateral line, the spots form a black line that stretches to the fish tail. Dorsal fin finishes in a black spot, while the caudal fin has vertical black stripes on it. There are no spots on the fish abdomen, and its color is light. The fish has three pairs of barbs near its mouth.

Corydoras julii grows up to 7.5 cm (3 in) long, but usually, it is smaller, about 5 cm (2 in) long. The fish lifespan is about 5-7 years, depending on the tank conditions.

Difficulties in keeping

This is a peaceful, schooling and relatively undemanding fish. However, I’d recommend beginner aquarists to try keeping some less demanding species, for example, adolfo’s catfish or panda cory.

Keeping in a tank

Like most of Corydoras species, julii is peaceful, and he will perfectly do for most community tanks. However, keep in mind that the fish should be kept only in a school. At that, the more fish you have in the school, the more comfortable they feel, and the more natural behavior the fish demonstrate.

Can julii corys live alone? No. The recommended minimum number of fish in the school is from 6-8 species.

One of the key requirements to create comfortable tank conditions for the fish is to have a non abrasive sand substrate, or it can be from small-sized pebbles. In the wild, fish constantly digs the bottom while looking for insects and their larvae.

The fish uses its sensitive barbs to find them, and if the tank bottom consists of large-sized or sharp pebbles, the fish can damage its barbs.

Small or medium-grained sand will be perfect as a tank bottom substrate, but small pebbles or basalt will do as well. Although the fish doesn’t need tank plants to feel comfortable, however, if there are some in the tank, they will make it look nicer and also create some shelters for the fish.

Besides, you can use some snags and fallen leaves together with the tank plants to make your aquarium look more natural, since these are the conditions that fish has in the wild. The corydoras julii prefer moderate water flow and clean tank water. It’s desirable to use an external filter, but for small-sized tanks, internal ones will do as well.

Optimal tank water parameters are the following: 72 – 78 °F (22 – 26 °C), dGH 2—20°, pH 6.0—8.0.


All Corydoras kinds are omnivorous, and they are bottom feeders. In most cases, they easily eat some drowning food (especially the one made for catfish), live and frozen food (they like tubifex), plant food pellets.

Diversified diet is the main thing for the fish to stay healthy and grow large. There is no way you can consider julii a picker and hope that the fish will only feed on what its tank mates haven’t eaten.

This fish requires a nutritious diet. You should make sure that it gets enough food, especially if many fish species dwell in medium water layers in your tank.

Tank mates

Corydoras julii is a perfect match for most small-sized catfish and other fish kinds. Possible tank mates are zebra danio, apistogramma Ramirezi, betta, shrimps (Amano shrimp, cherry shrimp) and even angelfish. You should only avoid keeping large and aggressive fish kinds (like oscar fish, green terror cichlid, jaguar cichlid, flowerhorn fish).

Gender differences: male vs female

Julii cory female is noticeably larger than the male. Besides, it has a more rounded abdomen, which is quite visible if you look at the fish from above.


Breeding is similar to that of most Corydoras species. You should put two-three julii cory males and one female in a spawning tank. When the female fish becomes fat with eggs, you should perform significant water renew with 50-70% of colder water and increase aeration and water flow in the tank.

If the fish doesn’t start spawning, repeat the procedure. The female fish lays eggs on tank plants and tank glass, and then the male fish fertilizes them. It is recommended to use caprone threads, since you can easily collect them after the spawning is over and remove the eggs to another tank.

You should remove the breeders from the tank after the spawning and move the eggs to another tank. The water parameters in this tank should be similar to those in the spawning tank.

Most of the aquarists add a few drops of methylene blue into the tank water to disinfect it and prevent fungal infection. The incubation period lasts for 3-4 days, and once the larvae eat all its yolk bag, the juveniles start to swim. You can feed juveniles with Vinegar eels, brine shrimp nauplii, and artificial food.

The julii cory juveniles require crystal clean water, and they are less prone to various illnesses if you put a thin layer of sand on the tank bottom.