Fun Jack Dempsey Facts For Kids

Aashita Dhingra
Jan 07, 2023 By Aashita Dhingra
Originally Published on Aug 06, 2021
Edited by Jacob Fitzbright
Jack Dempsey facts such as they are large and colorful freshwater fish are interesting.
Age: 3-18
Read time: 8.7 Min

Jack Dempsey cichlids are colorful fish originating from the freshwater lakes and creeks of southern Mexico, Honduras, Belize, and Guatemala. They are locally called the Mexican blue frontosa. These carnivorous fish have been introduced or have escaped to other water bodies in year-round warm climate areas.

These fish are popular pets for their beautiful coloration that may vary from beautiful blues, pinks, browns, and grays. These fishes also have attractive, shimmery dark blue, green, or gold blots on their bodies. Blots are more in number and prominence in the male Jack Dempsey.

A Jack Dempsey's natural habitat is a bog, swamp, and sluggishly moving streams. These fishes like to stay in sandy and muddy substrates.

Jack Dempsey cichlids are territorial fish and require big aquariums if keeping as pets. Their diet includes small fish, worms, crustaceans, and insects. In tanks, they can coexist with very few fishes of their size and predation status.

If feeling stressed or moody Jack Dempsey fish can change their color. They are a pleasure to watch in aquariums. Jack Dempsey cichlids may also change color with age. Juvenile fishes are less brilliant and have dull gray or tan coloration with pale turquoise flecks.

For more relatable content, check out these electric blue Jack Dempsey facts and convict cichlid facts for kids.

Jack Dempsey Interesting Facts

What type of animal is a Jack Dempsey?

A Jack Dempsey is freshwater fish that is named after the American boxing legend William Harrison Dempsey. These colorful cichlids are called the same names as the famous boxer Jack Dempsey due to their aggressive nature, and rugged facial features that match with the 1920s boxer.

The Dempsey’s attraction as an aquarium fish is due to its easy maintenance, breeding, and beauty that grows with age.

A male Jack Dempsey’s territorial attitude is typical of true cichlids. In the wild habitat, each male drives drive away other males from its territory on sight.

That does not make Jack Dempsey cichlids a good community tank fish species. Dempsey Jack cichlids need large tanks of a minimum of 50 gal (227 l) for a single and a 100 gal (455 l) tank if keeping a pair.

What class of animal does a Jack Dempsey belong to?

Jack Dempsey is a fish species belonging to the class Actinopterygii and the family Cichlidae. They are freshwater fish naturally occurring in Central and South America.

Over the years, like many other cichlid species, Jack Dempsey has had several other names. More than 100 years ago it was called Cichlasoma biocellatum, then Cichlasoma octofasciatum, changing to Heros octofaciatus. Then its scientific name was changed to Parapetenia octofasciata, then to Nandopsis octofasciata, next to Archocentrus octofasciatus, and finally to its current name Rocio octofasciata.

How many Jack Dempseys are there in the world?

It is difficult to tell the number of Jack Dempseys in the world as they live in their natural habitats in the wild in bogs and marshes.

Where does a Jack Dempsey live?

The Jack Dempsey, Rocio octofasciata, is a South American fish species naturally found in freshwater streams, bogs, marshes, and rivers of Mexico, Honduras, Belize, and Guatemala.

These fish have also been introduced in the United States, Asia, and Australia. Considered an invasive species outside its natural range, this is a fish that’s popular with aquarists.

What is a Jack Dempsey's habitat?

In the wild, a Jack Dempsey’s ideal habitat is warm, tropical waters. This fish species prefers stagnant or slow-moving water with sluggish currents. They are found in ponds, wetlands, bogs, rivers, swamps, and springs.

The wild waters where they live, are usually hard and alkaline with pH 7-8. Depending on the season, the water temperature range from 72-86 °F (22.2-30 °C). They can tolerate a large temperature difference in water conditions and are hardy fish.

To reach the optimal Jack Dempsey cichlid size, the fish needs to be kept in large tanks. Putting these fish in small tanks stunts their growth and does not provide them with a healthy life. Jack Dempsey fish care is simple but bigger tanks that are at least 55 gal (250 l) tanks should be provided for each fish.

Similar to other cichlids, the Jack Dempsey fish likes to dig in the sandy substrate looking for food. While setting a tank for a Jack Dempsey it is to be considered that the tank is not overcrowded with plants and accessories.

Some aquarists complain about Dempsey’s ripping up all the plants in the aquarium. Sand or gravel substrate works well for this fish species.

The colorful fishes look lovely against a dark substrate and their coloration can be enjoyed through the glass. As an adaptation feature, Jack Dempsey fishes alter their color to match the surroundings to camouflage. In a darker substrate, their pale purple or pink base color becomes dark, closer to black showing their blue iridescent spangles even better.

Give a Jack Dempsey fish tank a natural look with pieces of bogwood and large rocks. Place them carefully keeping in mind the fish’s digging habits. These middle to bottom dwellers need a combination of open swimming areas and large driftwood or plants for establishing territory and hiding zones.

Who do Jack Dempseys live with?

The large, ornamental Jack Dempsey fish are extremely territorial and do not live in shoals. A male and female can be kept in the same tank but not two males.

Young fish can still be kept together in tanks but before they reach sexual maturity they must be separated. Considering the large Jack Dempsey fish size, they should be provided spacious aquariums.

How long does a Jack Dempsey live?

Jack Dempsey fish lifespan is 10-15 years in the wild. Keeping Jack Dempsey fish is a long-term commitment and should be thought about before bringing them home.

How do they reproduce?

In their natural habitat, Jack Dempseys lay eggs on flat hard surfaces like rocks, and logs. In captive breeding tanks, they can be provided similar surroundings. These fishes care for their young.

Both parents take part in protecting the fry when they hatch. The unfertilized eggs are often eaten by adult fish. Jack Dempsey’s are known for pre-chewing food before feeding their offspring.

The female Jack Dempsey lays up to 800 tan-colored eggs. If in an aquarium, the size matters.

What is their conservation status?

The conservation status of the Jack Dempsey fish is of Least Concern according to the IUCN.

Jack Dempsey Fun Facts

What do Jack Dempseys look like?

A Jack Dempsey has an oval and stocky body.

Adult Jack Dempseys look truly stunning and that’s why these ornamental fishes have found their way into glass aquariums from their muddy and murky wild water habitats. A Jack Dempsey has an oval-shaped, stocky, compact body.

They are longer with large dorsal and anal fins. The tail is big and rounded.

The base body color of the fish ranges from a rosy pink to dusky gray and sometimes almost black color. Like all cichlids, Jack Dempsey's teeth are also sharp as they are carnivorous and prey on other aquatic creatures.

The most attractive feature of a Jack Dempsey fish is the body of the fish covered with metallic, iridescent blue-green blots. These spots reflect light and shine when the fish swims.

The most exotic of all Jack Dempsey’s is the electric blue Jack Dempsey. The variety of electric blue Jack Dempsey fish occurs naturally and is a color-morph of the Jack Dempsey species. A Jack Dempsey may take more than one year to mature and get its optimal coloration and spangled patterns.

How cute are they?

Jack Dempseys can be called beautiful but not cute.

How do they communicate?

Jack Dempseys communicate with their color and their movements. They alter body coloration depending on their mood.

How big is a Jack Dempsey?

The largest South American cichlid species is the wolf cichlids that can grow up to 24 in (61 cm). The Jack Dempsey fishes growing up to 10-12 in (25.4-30.5 cm) are half the size of wolf cichlid.

How fast can a Jack Dempsey swim?

The swimming speed of Jack Dempsey fish has not been recorded.

How much does a Jack Dempsey weigh?

Jack Dempseys weigh around 0.2 lb (0.1 kg).

What are the male and female names of the species?

The male and femaleJack Dempsey do not have any specific names.

What would you call a baby Jack Dempsey?

A baby Jack Dempsey is called a fry.

What do they eat?

One of the most important Jack Dempsey fish facts is they are carnivores and eat meaty things like worms, insects, crustaceans, shrimps, small fish. In home aquariums, feeding them with fresh food is a good option.

Pellets and flakes, and processed dried foods made for cichlids are good but occasional live food in the tank will provide the fish with the required nutrition. Bloodworms, brine shrimps, fruit flies, crickets, and grasshoppers, can be put in the tank as Jack Dempsey’s food.

Are they dangerous?

These fishes are big and fierce and can be aggressive too. They pose no danger for humans but for the smaller, and non-aggressive, Jack Dempsey tank mates.

Would they make a good pet?

Jack Dempseys make excellent tropical water tank fish. They are gorgeous to watch with their attractive colors.

The Jack Dempsey fish species is popular among aquarists as they are a hardy variety that’s easy to house and care for. It can be a wonderful fish for beginners as they are adaptive and not demanding in their preference for food and water conditions.

These large omnivorous fish species eat all kinds of live and fresh food like insects, worms, and small fish. They can also be fed flake or pellet food.

A Jack Dempsey fish grows big in the wild. A male Jack Dempsey fish size can be more than 12 in (30.5 cm) and females up to 10 in (25.4 cm). In spacious aquariums, the males can grow up to 10 in (25.4 cm) and the females up to 8 in (20.3 cm).

Did you know...

One thing to remember when keeping a Jack Dempsey is that the fish’s natural habitat ranges from Mexico to Honduras where the water temperatures are warm. To provide proper Jack Dempsey cichlid care with similar environments, a heater in the tank is necessary.

Keeping Jack Dempsey fish

Jack Dempseys cannot be kept with all kinds of fishes because they will kill smaller fish. The most suitable tank mates that may coexist and breed with Dempsey’s are other varieties of large Central American cichlids.

Identifying Jack Dempsey fish

The cheeks are the identification spots for telling a male Jack Dempsey from a female. A male fish has bluish spots right behind the eyes, and no spots are present below the mouth. Females have extended markings on the full length of the cheek and large iridescent blotches below the cheek.

The tail fin is also different in both sexes. Males have pointed edges and the females have rounded edges on their tails.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! Learn more about some other fish from our wreckfish fun facts for kids and kissing gourami surprising facts pages.

You can even occupy yourself at home by coloring in one of our free printable Jack Dempsey coloring pages.

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Written by Aashita Dhingra

Bachelors in Business Administration

Aashita Dhingra picture

Aashita DhingraBachelors in Business Administration

Based in Lucknow, India, Aashita is a skilled content creator with experience crafting study guides for high school-aged kids. Her education includes a degree in Business Administration from St. Mary's Convent Inter College, which she leverages to bring a unique perspective to her work. Aashita's passion for writing and education is evident in her ability to craft engaging content.

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