Freshwater Aquarium Fish Profile: Julii Corydoras(Corydoras julii)

The Julii Corydoras is a very popular aquarium fish among the pet fish keepers due to its brilliant body coloration and appearance. Austrian ichthyologist Franz Steindachner first described the species ‘Julii Corydoras’ (Corydoras Julii) in 1906. It has placed in Callichthyidae family under order Siluriformes of class Actinopterygii (=Osteichthyes).

Systematic Position

  • Phylum: Chordata
  • Sub-phylum: Vertebrata
  • Class: Actinopterygii
  • Order: Siluriformes
  • Family: Callichthyidae 
  • Genus: Corydoras  
  • Species: Corydoras julii

Distribution and Habitat

In Nature, it is found in Amazon River basin of Brazil. It occupies in creeks, rivers near coastal region, flooded areas of Amazon forest region and its tributaries. It is a community fish and prefers to form school with up to 30 individuals or more.

Common Names

It is also referred to as Julii Catfish, Julii Cory, and Leopard Cory.

Body Shape

Body is small with moderate forked caudal fin and blunt snout. Head is short with arched back and erect dorsal fin. It has adipose dorsal fin which is placed just above the anal fin. The body is scale less with scutes or overlapping hard plates. Mouth is moderate and terminal which is surrounded by some barbells. 

Julii Corydoras

Body Colors and Decorations

Generally body is transparent whitish grey in colors with distinctive black dots on the head and body. A dark crisscross stripe is seen along the lateral line which runs from the gills to the caudal fin. It has transparent dorsal fin but a large black mark is present on the upper side of fin while vertical rows of dark brown spots are present on the caudal fin (tail fin). Beside these the anal, pectoral, pelvic and adipose fins are whitish in color with spots.

Quick Julli Corydoras Fish Facts

  • Scientific Name:Corydoras julii
  • Origin: Amazon River
  • Family:Callichthyidae
  • Grown up Size: 6 cm
  • Temperament: Peaceful
  • Tank Level: Bottom
  • Minimum Tank Size: 15 gallons
  • Diet: Omnivore
  • Breeding: Egg layer
  • Water pH: 6.5-7.5
  • Hardness: 8-12°dGH
  • Temperature: 70 – 80°F
  • Lighting needs: Normal-moderate
  • Care level: Easy
  • Lifespan: 5 years

Food and Feeding Behavior

It is an omnivore and it mainly feeds on zooplankton such as Daphnia, Moina, Rotifers, Brine shrimp, insect and its larvae (Chironomus),oligochaetes (Tubifex) and vegetable matters. In aquarium, it also takes different type of commercial foods such as flakes, granules, tablets and pellets (shrimp pellets, Cory pellets). It is an active during the night time and feed should be given one time. It needs at least 30 minutes to consume food due to slower eater.

Housing and Care Facts

It is a community and peaceful fish. It needs at least 15 gallon tank with lots of dark substrate, driftwood, hiding spots and open areas for free swimming. The tank should have well filtration system, well oxygenated good waters with a pH of 6.5-7.5, hardness of 8-12°dGH and temperature that should be ranged between 70 and 80 °F. To make your tank environment healthy, 20-25% water change should be done every other week.


It should be kept with 5 or more individuals. In this case, any large or aggressive fish should be avoided. Best tank-mates are Rasboras, Dwarf Cichlids, Cockatoo cichlid, Danios, anabantoids, small characins and cyprinids.

Breeding Behavior

It can easily breed in aquarium condition if appropriate care is taken. The tank should be decorated with aquarium plants, sand or gravels. To stimulate the breeding, parents should be fed with meaty food. In this case, live foods such as bloodworms (Chironomus larve), Daphnia, brine shrimp, tubifex are suitable. The mature female lays sticky eggs on the aquarium surface. The eggs hatch within 5 days. After few days, the fry becomes free swimming and they should be fed with newly hatched brine shrimp, rotifers and any liquid fry food.

Male and Female Sex Differences

Generally, the male is smaller than the female of same age. The female belly is rounded and during the breeding season, female body looks plumper when she bears eggs in her belly.

Disease and Preventive Measures

Julii Cory is a very hardy fish but sometimes it is affected by bacterial diseases due to inappropriate maintained aquarium environment. In this case, nitrate level should be maintained below 20 mg per liter of water. Generally, high nitrate level can affects the barbells of the corry catfish.  To maintain nitrate level suitable, 20-25% water changes should be done regularly. Affected fish should be treated with pimafix or melafix with recommended dosages.  To prevent disease, balanced diet should be provided and appropriate care should be taken.

Also Read: Beautiful Glass Catfish Info

Final Verdict

The Julii Cory is a very attractive and popular fish among the pet fish enthusiasts due to its brilliant body coloration and hardiness. It is now available in the pet fish markets and online shops with reasonable price. To make your aquarium attractive, you should keep this gorgeous fish in your aquarium. You can also read read about Bala Shark or Zebra Danio as both of them can also make it to your aquarium.

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