Jack Dempsey Fish Care Guide

Jack Dempsey fish

Last updated on August 14th, 2022 at 12:55 am

The jack dempsey fish is a great freshwater fish for new aquarium owners. It’s also a good choice for people with saltwater tanks who want to add some variety to their tank populations. They have been on the endangered species list, but you can find them at most pet stores or online if you know where to look!

The jack dempsey is a large predatory fish that can be found in the Amazon River and other South American waterways. They are nicknamed “water wolves” because they hunt in packs to take down prey bigger than themselves, such as turtles or even small alligators.

In the aquarium, the jack dempsey is a very active fish and will often swim to the top of the tank to take in air. They are carnivores and should be fed a diet of live or frozen foods such as bloodworms, brine shrimp, or krill.

They make an excellent addition to any home aquarium and can be easily cared for by anyone with basic fishkeeping experience. If you’re looking for an interesting and unique freshwater fish to add to your tank, the Jack Dempsey is definitely worth considering.

Origin and descriptions

Jack Dempsey fish

The Jack Dempsey fish is a freshwater fish that is native to North and Central America. It is a popular aquarium fish because of its bright colors and active nature. They can grow up to 20 inches in length, making them one of the larger members of the cichlid family.

This fish gets its common name from the famous boxer Jack Dempsey. The fish was named after the boxer in 1928 by a Long Beach, California Aquarium owner who claimed that his new acquisition had picked up a habit of attacking and eating other fish larger than itself within 24 hours or less.

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The “Jack Dempsey” is one of the most popular cichlid fish kept as pets in the United States.

Species profile

Jack Dempsey fish

The Jack Dempsey is a cichlid fish, native to Central America. It has been described as the largest of all freshwater fishes in North and South America. They can be found living in rivers and lakes in areas such as Costa Rica and Guatemala. The species is known for its aggressive behavior towards other fishes and its large size which can reach up to 24 inches in length.

The Jack Dempsey is a popular aquarium fish and can be found in home tanks across the world. They are relatively easy to care for and will eat most types of food, making them an ideal choice for beginner aquarists. The males are highly territorial and will defend their territory against other males as well as females. As a result, it is recommended to keep only one male per tank.

Scientific name

The scientific name for the Jack Dempsey fish is Rocio octofasciata


They live in a tropical climate with water temperatures between 72–78 degrees Fahrenheit. Jack Dempsey lives in the waters of Belize, Costa Rica, and Panama.

They prefer slow-moving rivers with dense vegetation to hide from predators such as jaguars and caiman crocodiles. They also prefer shallow areas where they can find more food.

Jack dempsey fish size and weight

They can reach a size of up to 24 inches and weigh up to around 15 pounds.

Jack dempsey fish growth rate

They are fast growers. They can grow up to twelve inches in their first year, and reach maturity at around four years of age.

Males will get larger than females but males also have longer fins which make them appear bigger when they flare out while the female’s tail is shorter.

Females usually grow faster because they grow larger and have a more rounded dorsal fin.

Jack dempsey fish tank size

The Jack Dempsey fish is a territorial fish and should only be kept in tanks that are at least 125 gallons.

Tank setup

A Jack Dempsey fish tank should have live or plastic plants on the sides of the tank to provide hiding places.

The bottom of the tank should be covered with gravel and some driftwood can be used for decoration too. The water temperature in a Jack Dempsey fish tank needs to stay within 72–78 degrees Fahrenheit, so you will need an aquarium heater to keep the water at that temperature.

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The Jack Dempsey fish feeds on insects, shrimps, and smaller fish such as guppies or platys. You can feed them high-quality flake food but also live foods like crickets, worms, and small frogs if you have access to those animals. Cleaning of an aquarium with a Jack Dempsey fish should only be done every other week.

Jack dempsey fish tank mates

The Jack Dempsey can be kept together with other fish in a tank but they will become more aggressive towards the same species if the numbers are too high.

They should not be kept with any kind of cichlid or catfish since these fishes have teeth that could damage their mouths which would lead to infections for both fishes.

Some good tank mates for the Jack Dempsey would be angelfish, gouramis, barbs, and tetras.

Breeding and Life cycle

The Jack Dempsey fish is a prolific breeder and will lay eggs up to three times a month. The eggs will hatch in two days after fertilization and the fry will be able to eat flake food from that point onwards.

They can become sexually mature when they reach a size of six inches and will usually live for eight to ten years.

Is a Jack Dempsey fish aggressive??

Yes. Jack Dempsey fish are aggressive and considered to be one of the most aggressive cichlids. They can become very territorial when they reach a size of six inches, since this is usually around the time they will try to breed too.

The Jack Dempsey needs its own tank with plenty of hiding places because it won’t back down if another fish enters his territory.

The fish can become very aggressive when it is in breeding condition, so the tank should only have one male and several females to reduce aggression between males during this time.

Jack dempsey fish care

Jack Dempsey fish

Caring for Jack Dempsey fish is not difficult. You need to provide them with the proper housing and give them a good diet. A 60-gallon aquarium will work for one Jack dempsey, but if you plan on keeping more than one, it is best to upgrade so they have plenty of room.

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The substrate can be any gravel or sand that does not have sharp edges. If you use sand, make sure it is a smooth grain, and the bottom of the tank should be covered with gravel or rocks to protect the fish from injury if they jump out.

It’s best to keep your Jack Dempsey in an aquarium that has live plants because they love to play around them and hide among them. But every once in a while, they will eat the plants, so you might want to add some fake ones too.

Your Jack Dempsey will need a good source of protein in their diet.

Jack dempsey fish food

Feeding your Jack Dempsey fish a good commercial flake food or pellet is the best way to keep them healthy. They also love bloodworms, brine shrimp, and other meaty foods such as krill or beef heart.

They will get enough protein from these types of pellets but you should give them some live feeders once in a while. Earthworms and bloodworms are some of their favorite foods to eat, but they will also feed on insects if they can find them.

If you don’t have live food available, your Jack Dempsey fish may not get enough protein in its diet which is important for proper growth development. Young dempsey needs lots of protein, so it is best to buy them at least two to three times a week.

When feeding your Jack Dempsey fish, feed small amounts of food several times throughout the day rather than one large feeding. This will help ensure that they are getting enough protein in their diet and also prevent bloating which can be fatal if not treated quickly.

Water conditions

Jack Dempsey fish

Jack Dempsey fish need water that is clean and well-oxygenated. The pH should be around neutral (between pH of six and eight) and the water temperature should be kept between seventy-five to eighty-five degrees Fahrenheit.

Make sure you do regular water changes to keep the ammonia, nitrite, and nitrate levels in check. These levels can be harmful to your Jack Dempsey fish and can cause health problems.

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It is also a good idea to add a water conditioner to the aquarium that will help keep the water clean and free of harmful toxins.


The average lifespan of a Jack Dempsey fish is six to eight years. But with proper care, they can live up to ten years or more.

Parasites and diseases

Jack Dempsey fish are susceptible to a number of parasites and diseases. Some of the most common ones are ich, velvet, Trichodina, and fin rot.

If you notice any signs of illness or parasites in your fish, take them to a qualified aquarium store or veterinarian for treatment. Early diagnosis and treatment are essential for the successful treatment of most diseases.


Jack Dempsey fish are not usually a target for other animals, but there are other species that can cause them harm. These types of predators include pufferfish and bass.

The best way to avoid any problems with these predators is to keep your Jack Dempsey in an aquarium by themselves or place some type of barrier between the two if they need to be in the same tank.

Do they make good pets?

Yes. Jack Dempsey fish make excellent pets for those who are willing to care for them properly. They are active, playful, and can be quite entertaining to watch. They do require a lot of attention and need a good diet and healthy environment to stay healthy. But with a little work, they can make great additions to any home aquarium.

Do Jack Dempsey fish eat other fish?

Yes, they do. They are a predator and not a herbivore or omnivores so it is part of their nature to find food that will satisfy them nutritionally while still being able to hunt for live prey. In general, they will eat fish that can fit in their mouth.


The Jack Dempsey fish is an interesting and beautiful addition to any aquarium. They are relatively easy to care for, but do require a large tank with plenty of hiding places. They are carnivores and will eat other fish, so be sure to research the types of fish that can live safely in an aquarium with a Dempsey before adding one.