Julii Corydoras

How to Take Care of Julii Corydoras (Infographs)

Julii Corydoras Julii (Corydoras julii) are attractive Corydoras with dark markings and spots against it silver body. It is often confused with Corydoras trilineatus or Three Striped Corydoras.  Originating from the rivers and streams of South America and Central America, there are over 150 different species of Corydora catfish. Corydoras Julii are bottom dwelling fish that will scavenge and clean your aquarium. They are easy and hardy fish to care for because they can tolerate a wide range of water parameters. Corydoras Julii are also peaceful and social, making them excellent fish for beginners looking to add bottom-dweller fish in their community tank. 


NameJulii Corydoras
Scientific NameCorydoras julii (also called Corydoras leopardus)
OriginSouth America
Size2.5 inches (6 cm)
Minimum Tank Size20 Gallons
Ease of CareEasy
PHPH 6.0-7.0
Water Temperature73-79F (23-26C)
Water Hardness LevelSoft to Hard (50-150mg/l)

What are Other Names for Corydoras Julii

Julii Corydoras are also called Julii Corys, Julii Catfish or Leopard Cory.

How Big Do Corydoras Julii Get?

Julii Corydoras can grow to 2.5 inches (6 cm).

What to Feed Corydoras Julii?

Julii Corydoras are omnivores. Corydoras Julii are bottom dweller fish that will feed on uneaten food. Even though they are scavengers, you still need to feed Corydoras Julii their own food. It’s not enough to rely on food collected from scavenging as their only food source. You should supplement their diet with sinking pellets that are formulated for bottom-dwelling fish. 

How to Set Up an Aquarium for Corydoras Julii?

Julii Corydoras will thrive in a well planted aquarium with open swim areas. Corydoras Julii spend their day digging and will use their mouth to dig the substrate. Use fine substrate like sand instead of gravel in your aquarium to make it easier for Corydoras Julii to dig and to prevent damaging their whisker-like barbels. Provide plenty of plants and rocks/shells for cover so your Corydoras Julii will feel protected and safe. 

What are the Best Water Parameters for Corydoras Julii?

Julii Corydoras are tolerant of a wide range of water parameters but should not be in excessively acidic water conditions.

What is the Ideal Water Temperature for Julii Corydoras?

Corydoras Julii should be kept in a tank with a water temperature of 73-79F (23-26C).

How to Set-Up Your Tank for Breeding Corydoras Julii?

Set up a breeding tank with 1 male and 2 female Corydoras Julii. Make sure the breeding tank is well-planted so Corydoras Julii can lay their eggs on the plant leaves (Java Moss). You can also use spawning mops.

Set up the breeding tank with fine substrate like sand or keep the tank bare without any substrate. Add one or two pots or big shells, so your Corydoras Julii can hide and feel safe during spawning. For optimal breeding conditions, it’s important to keep your Corydoras Julii well fed. 

Use a sponge filter in the fry tank. Sponge filters are gentler and will not suck up the Corydoras Julii fry. 

How to Breed Julii Corydoras?

Julii Corydoras are egg layers. Breeding occurs with the female Corydoras Julii swallowing male sperm and then releasing the sperm from her gut to her cupped pelvic fins along with some eggs. She will lay these eggs in small batches on plant leaves or on the aquarium surface.

The eggs will hatch 5-6 days later. After hatching, the young Corydoras will stay on the substrate and consume their yolk sac until they become free swimming. Once they are free swimming, feed the young Corydoras with fish food specifically for fry or freshly hatched brine shrimp.

How to Get Julii Corydoras to Start Spawning?

Here are 3 things you can do to trigger spawning 1.) Do a partial cold water change. Add colder water into the tank. This will bring aquarium water temperature down a few degrees which will simulate the water temperature after a heavy rainstorm. 2.) Feed your Corydoras Julii high protein, high nutrient food. Keeping them well-fed will condition your Corydoras Julii for spawning. 3.) Increase airflow in your aquarium. The increased airflow will simulate the strong river currents after a rain storm. This will trigger spawning. Under the right conditions, your Corydoras Julii will start spawning.

See below for an inforgraph on how to get your Julii Corydoras to start spawning.

Will Adult Corydoras Julii Eat Their Eggs?

Julii Corydoras will eat their own eggs and fry. You will need to separate the adults from the eggs. The best way to do this is to move the eggs to a fry tank. You can also move the eggs to a breeding box.

If the eggs are on plant leaves, remove the entire plant and transfer it to the fry tank. If you are using a breeding box, you can gently remove the eggs one by one with your fingers and transfer them to the breeding box. If the eggs are on the aquarium glass, gently scrape off the eggs with your finger and transfer them to the fry tank. You can also use a credit card to scrape eggs off the aquarium glass. Corydoras Julii will lay eggs in many different places so you should check the entire aquarium for eggs- behind filters, on plant leaves, aquarium glass, shells, etc.

Make sure the water parameters and water temperature of the fry tank are similar to the breeding tank.

How to Prevent Fungus on Julii Corydoras Eggs

Add a few drops of methylene blue to the fry tank to prevent egg fungus. Once the eggs hatch, remove the methylene blue because it will be harmful to the fry. You should also aerate the tank with an airstone or sponge filter. This will help prevent fungus from developing on the eggs.

Below is an infograph on how to prevent egg fungus when breeding Julii Corydoras.

Are Julii Corydoras Peaceful or Aggressive Fish?

Julii Corydoras are peaceful fish. Making them good tankmates in community tanks. 

How Many Corydoras Julii in a Tank?

Julii Corydoras are not solitary fish. They are social fish that should be kept in groups of the same species. If space permits and without overstocking your tank, keep at least 5 Corydoras Julii in your tank. 

Use our How Many Fish in a 10 Gallon Tank Calculator to find out how many Corydoras Julii you can keep in a 10 gallon tank. For 20 gallon tanks, use our How Many Fish in a 20 Gallon Tank Calculator to find out how many Corydoras Julii you can keep in a 20 gallon tank.

What Fish are Compatible with Julii Corydoras?

Julii Corydoras are compatible with most peaceful topwater and midwater fish that share similar water parameter requirements. There are a lot of fish that are compatible with Corydoras Julii such as livebearers like guppies, swordtails and platies. Other popular community tank fish such as Zebra danios, rasboras and tetras are also compatible with Corydoras Julii. 

Do I Still Need to Clean the Aquarium Since Corydoras Julii are Tank Cleaners?

Even though your Julii Corydoras are tank cleaners, you still need to clean the aquarium. Perform partial water changes at least once every 3 weeks. This will keep nitrate levels low and help maintain optimal water quality.

Use a gravel cleaner to remove dirt buildup on the substrate during partial water changes. Dirt buildup on the aquarium substrate can damage your Julii Corydoras whisker-like barbels.

Check out our article on How to Clean Your Aquarium in 15 minutes

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