Julidochromis Regani (Convict Julie)

Julidochromis regani

Last updated on August 18th, 2022 at 04:56 pm

Julidochromis regani (Convict Julie) are one of the most popular dwarf cichlids in the aquarium hobby. They have earned their popularity through their hardiness, behavior, and relatively small size.

Julidochromis regani, also known as Convict Julie or Regan’s Julie, is a species of fish in the Cichlidae family found in Mozambique and Tanzania. It was originally collected in Lake Nyasa, but has since been found in other locations and recently around coral reefs off of the coast of Mozambique and Tanzania. This species reaches about 4 inches (10 cm) long and requires an aquarium of 50 gallons with plenty of open swimming space, particularly if kept singly.

Convict Julie is an African cichlid endemic to Lake Malawi. This species primarily feeds on snails, clams, arthropods, and benthic algae. But how did they get their name? What do you need to know about caring for this species?

Read on to find out more…

Origin and descriptions

Julidochromis regani

The Convict Julie, or julidochromis regani is a freshwater fish endemic to Lake Malawi in Africa. It was first collected in 1938 by D. H. Regan and named after him, but it wasn’t until 1991 that he was finally recognized as its discoverer.

However, no one knows for sure what type of breeding habits julidochromis regani possesses since there are no living examples of them out of their natural habitat at that time. They are found at depths of about 30 meters throughout large swaths of water between two areas called Mafia Island and Nkhata Bay.

They have been characterized as carnivorous bottom-dwellers who like to snack on small crustaceans, worms, mollusks, annelids, plankton, and zooplankton alike. Their bodies can be anywhere from 4 cm long up to 10 cm long depending on age: they grow larger with age and maturity.

Convict julies are from Lake Tanganyika in Africa. The species are from Lake Tanganyika in Africa. The species is limited to a small number of cichlids on one side of that lake and because of that, it should not be mixed with fish from another location.

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Species profile

The Convict Julie, or Julidochromis regani, is a dwarf species of cichlid endemic to Lake Tanganyika. It is found in areas with rocky substrates and prefers caves and crevices for cover. They are omnivores that feed on algae, plants, small crustaceans, worms, and insect larvae. The female lays approximately 20 eggs at a time on rocks in its cave habitat; both parents guard their offspring as they grow.


Regan’s Julie is a lake-dwelling cichlid native to Lake Tanganyika in East Africa. This species is listed as Least Concern on the IUCN Red List of Threatened Species and as of December 5, 2013, it is not considered to be threatened by exploitation or habitat destruction. Because it lives in Lake Tanganyika, it can only survive in waters with a salinity range between 15-35 parts per thousand and temperatures between 22-30 degrees Celsius.

Julidochromis regani size

This species of fish can grow up to 5.1 inches (13 centimeters) in total length.

Julidochromis regani tank size

The minimum recommended tank size for Julidochromis regani is 50 gallons for a single fish and 75 gallons or more for a pair.

Tank set up

Regan’s Julie can be kept in a freshwater aquarium with the water temperature at 20.0 – 24.0 degrees C (68.0 – 75.2 degrees F). A pH of 7.8 – 8.6, dH of 10-25 degrees, and a water hardness of 2 – 25 NK° are recommended, though they are adaptable to minor variations in these ranges, as long as extremes are avoided and stability maintained.

It should preferably not be kept with aggressive or very territorial species such as some cichlids, gouramis, or other livebearers because it will likely be outcompeted for food and space. It fares best when kept in a pair or group of 6+ specimens but can also be kept singly if provided with sufficient hiding places.

Julidochromis regani tank mates

While all cichlids should be kept in species-only tanks to prevent hybridization, some saltwater cichlids can get along in a community tank with peaceful fish of their own kind. This includes Convict Julie, as well as other Saltwater Dwarf Cichlids like Jack Dempsey Cichlids, Flamefish, and Gobies. Many larger cichlids can prey on them or bully them out of food and territory, however.

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Other good tank mates for Convict Julie are schools of smaller fish like damselfish, but keep in mind that because Convict Julie is a dwarf cichlid, it can be easily outcompeted for food by larger fish. It’s best to keep them with other species of dwarf cichlids or similarly sized saltwater fish.

Julidochromis regani breeding

Julidochromis regani

Julidochromis regani are egg layers. They will lay up to 4 egg clutches at a time and will spawn several times during a breeding season. Although, they can also be sexually monomorphic, meaning that some fish have male characteristics while others are female. This makes it difficult to determine whether or not your fish is male or female. So, if you’re planning on breeding them, ensure you purchase multiple fish.

A good ratio would be 1 male to 3 females. To induce spawning, feed your fish live foods or brine shrimp as well as provide ample hiding spots for mating. Spawning should occur quickly once they are ready. The easiest way to sex convict julies is by observing their fins; males have longer fins than females. They require very clean water with a lot of oxygen to thrive in captivity.

Provide them with plants, driftwood, caves, and rocks to make sure they get enough oxygen from the water surface. If your water quality isn’t what it needs to be, try supplementing aeration within your tank.

Are Julidochromis regani aggressive or peaceful?

Convict julies are generally peaceful, but there is always a chance that one could behave aggressively if not given enough room or if it feels threatened. Since they can live in schools of up to 20 fish, they should be kept in groups of five or more. When mixed with other species, these fish do fine as long as they are given enough space.

Julidochromis regani care

Julidochromis regani

Regan’s Julie is an easy fish to care for, as long as its water is clean and it is well fed. The tank should be set up with lots of hiding places for Regan’s Julie to feel safe and secure, such as caves or plants. They like live plants in their tank, such as Anubias, Java Fern, Amazon Sword Plant, and Cryptocoryne wendtii.

Checkered Julie Cichlid (Marliers Julie)

It does not harm them if these are placed directly into their mouths; they actually find them enjoyable. Like most other cichlids, Convict Jullie appreciates a good gravel substrate and plenty of rocks to perch on. They also enjoy a sandy substrate that they can dig around in while they search for food.

Julidochromis regani food

Julidochromis regani are omnivores, which means they will eat just about anything. In an aquarium, they can be fed sinking pellets, algae wafers, flakes, and bits of frozen foods such as brine shrimp or daphnia. Although with most fish you can get away with leaving their food out all day long it’s best to limit feedings to twice a day when possible.

This keeps water quality high since uneaten food left in your tank decomposes and lowers your water’s pH level. It also reduces aggressive feeding behavior by giving other tank mates time to eat before more food is added.

Your convict julie should always have access to both plant matter and meaty items in its diet – use at least two different types of leafy greens as well as live or frozen bloodworms, tubifex worms, mosquito larvae, and blackworms.

Water parameters

Julidochromis regani

Water quality is crucial for a healthy aquarium and varies slightly with each species. Specific gravity should be kept between 1.020 and 1.025, with a pH of 8.0 to 8.4 and an overall hardness level of 12 to 15 dH. The water temperature should remain at a stable 24-27 degrees Celsius, but can drop to 20 degrees at night in order to replicate conditions in their natural habitat; water flow should be minimal for these fish as well!

Both water flow and currents may also stir up substrate material, so sand or fine gravel is best for them. Be sure to include hiding places among rocks or driftwood as these dwarf cichlids enjoy solitude from time to time.

Julidochromis Marlieri (Marlier's Julie)

Julidochromis regani lifespan

On average, Julidochromis regani are fairly long-lived for a dwarf cichlid species, and they can live up to 10 years with good care.

Parasites and diseases

Parasites are a concern with livebearers, so keep an eye out for them. Treat your tank with a parasite-control product like PraziPro. Another culprit to look out for is Ichthyophthirius multifiliis or Ick for short. Symptoms include clamped fins and lethargy; you can often see little white spots on your fish’s body as well.

Ick can be treated with raised temperature and medication, but if it gets bad enough, it could mean death for your fishes. Last but not least, Convict Julie can succumb to swim bladder disease —they’re prone to bloating due to their lack of buoyancy control—so be sure not to overfeed and take care when acclimating new fish into an existing community. You’ll also want to treat external parasites like anchor worms.


The known predators of julidochromis regani include but are not limited to Goliath tigerfish and other piscivorous fish species. As with most cichlids, it is assumed that anything that can fit into its mouth will potentially eat a convict julie, including humans. When adding any fish to an aquarium environment, one must also assume they may be food for their tank mates.

Do Julidochromis regani make good pets?

Yes. As a result of their small size, ease of care, and relatively peaceful disposition, Julidochromis regani are a great fish for beginners. Unfortunately, because they are so attractive and easy to keep, many species in this genus have been taken from Lake Tanganyika for aquarium use at unsustainable rates. This practice has led to several species being threatened with extinction.