Jack Dempsey Fish Care Guide: Tank Setup and More – 2020


Although Jack Dempsey Fish is a popular fish among aquarists but not for beginners, an aggressive fish, Jack Dempsey, is not easy to care. But aquarists love to have the fish in their aquarium due to their peculiar color and shape.


In this blog, we take a look at interesting facts about freshwater fish. It includes the fish’s ideal diet, tank conditions, aquarium tank mates, and other information. After reading the Jack Dempsey care guide, you will know how to handle the fish in an aquarium.


Category Rating
Level of Care Intermediate
Temperament Aggressive
Appearance Grey color and bright flecks
Life Expectancy Up to 10 years
Size Up to 15 inches
Diet Carnivore
Family Cichlidae
Tank Size 80 Gallons
Water Conditions 75°F – 80°F (24°C – 27°C); pH level 6-7
Tank Environment Dense vegetation and floating plants
Aquarium Tank Mates Aggressive fishes of same size


Jack Dempsey Overview 

Jack Dempsey is a freshwater fish that belongs to the Cichlidae family. The fish got its name after the legendary heavyweight boxing champion Jack Dempsey due to its aggressive nature. 

It can grow to a size of up to 10 inches. Males generally grow to a larger size as compared to females.


Natural Habitat


Jack Dempsey is native to rivers and streams in Guatemala, Belize, Mexico, and Honduras in Central America and slow-moving rivers, lakes, streams, and canals.


The fish also has a habitat in the US, Russia, Australia, and Asia, where they are considered an invasive species. Jack Dempseys prefer warm waters and thrive mostly in tropical climates. They live in water streams with sandy and muddy substrates.


Jack Dempsey Appearance


The fish has a large oval-shaped body with long fins. The males are generally larger than females. They are available in a wide variety of colors, which include pink, gold, and blue.


Jack Dempsey’s color changes with age. The younger fish may be pale grey with green dots. As the young ones grow up, their color becomes dark purple-gray with blue-green flecks.


Jack Dempsey’s color can change temporarily, as well. The fish turns dark when it is mating and pale when feeling threatened.


The body shape of males and females are different. Males have a longer dorsal fin and more pronounced tips than females—Jack Dempsey’s body ha iridescent blue or green spangles or spots that look attractive.


These spots flash brightly under the light as the fish swims inside an aquarium. The shimmer and shine of the fish look almost surreal. The older and larger Jack Dempseys have more pronounced iridescent spangles as compared to the smaller ones.


Jack Dempsey Behavior


Jack Dempsey shows highly aggressive tendencies. Many beginner aquarists struggle to keep the fish in their tank. The fish is less likely to show aggressiveness in tanks populated with lots of other fishes. It won’t have the opportunity to attack a stray fish in populated tanks.


A male Jack Dempsey may attack others to establish a territory. To reduce territorial disputes, you should consider placing plenty of caves and other objects with crevices inside the tank. The fish mostly stay in the lower or middle level of the tank. Some are somewhat shy and prefer to hide inside the cave.


Jack Dempsey Aquarium Tank Mates


When it comes to Jack Dempsey’s compatibility with others, it is exceptionally restricted as it is a highly territorial fish. It doesn’t survive well with other species. The fish often bites its tank mates with its sharp teeth. Therefore, your options may be limited when it comes to buying a tank mate for the fish.


It is essential to choose aquarium tank mates of the same size and nature as the Jack Dempsey fish. Avoid keeping species that can easily fit its mouth. Also, avoid keeping peaceful species that can’t defend themselves. Smaller species like tetra are likely to be eaten up by the Jack Dempsey, while may harass the temperate species to the point of death.


Some compatible aquarium tank mates for the Jack Dempsey fish include:



You can also keep invertebrates like small snails and shrimps with your Jack Dempsey fish. But the fish is likely to treat them as food.


As a result, other species of Jack Dempsey are its best aquarium mates. However, do not place more than one male in the same tank because it can lead to a fight.


Tank Conditions for Jack Dempsey


Jack Dempseys live in the wild in waters that are soft with an acidic pH. However, they are adaptable and can thrive in a variety of water conditions. Ideal tank conditions for the fish include water temperature between 75°F and 80°F (24°C – 27°C) and pH level of water between 6.5 and 7.


The nitrate in the water should be less than 40 ppm. The degree of general hardness of the water should be between 9 and 20 dGH. Make sure to replace about 10 percent of the water every week, 20 percent every two weeks, and 40 percent water every month.


Avoid replacing all the water since it will remove essential bacteria and cause a shock to the fish, due to which it will become stressed and susceptible to diseases.


Jack Dempsey Tank Setup


The size of the Jack Dempsey fish is relatively large. You should keep the fish in a large tank with about 80 gallons of water. Each fish will require about 55 gallons of water in the tank. Jack Dempseys’ tank size should be large enough to allow the fish to swim freely inside the aquarium.


Select a soft substrate so that the fish does not injure itself while spending time at the tank’s bottom. The fish look great in a dark substrate.


They may change color to match their surroundings. So if you place dark color substrates, the fish’s body color will turn brown or black, making their iridescent spangles more attractive. A light color substrate makes the fish appear washed-out pink or purple color.


Avoid purchasing sand that some sold as ‘cichlid sand.’ The reason is that cichlid sand consists of a crystallized calcium carbonate (CaCO3), known as aragonite. 


Aragonite sands leak calcium carbonate in the water that can increase the water’s pH level and hardness. You can consider buying an inert substrate that will not make the water hard and acidic.


Also, add plants to the aquarium. But, make sure the plants have hardy leaves that cannot be quickly nipped by the fish. You can consider getting floating plants like Hornworts to bring greenery to the aquarium and comfort to the fish. Other options include Java Fern and Anubias as Jack Dempseys find their taste repulsive and are less likely to uproot the plant.


Adding a water heater inside the tank is recommended to maintain the right temperature. Jack Dempsey can live in the warm waters of Central America. Consider buying a gigantic heater that will heat the water quickly to the desired temperature. There is no need for a giant-sized heater at all times, which will significantly increase the heater’s lifespan.


A good quality filter is also required to process the waste of the fish. Jack Dempsey is a large species that creates a lot of waste, which sinks to the bottom of the tank and releases ammonia (NH3) that can be toxic to fishes. Having a filter will prevent the buildup of ammonia inside your aquarium.


Lastly, do not forget to add decorative pieces inside the tank. Jack Dempseys love to hide inside caves. They establish their territory near the cave, so you need to have multiple shelters if you have other species inside the tank. The cave should be large enough to allow the fish to hide inside when it feels threatened. Large size rocks are also right hiding places for the fish. You can add pieces of driftwood that the fish can hide behind when it gets scared.


jack dempsey






Jack Dempsey Fish Food: What to Feed Your Jack Dempsey Fish?



Jack Dempsey is a carnivore that means that the fish should be fed meat only. A good thing about the fish is that it is not a picky eater. You can feed it insets, worms, crustaceans, and small species. You can also give them processed food items, including flakes and pellets specially made for cichlids.


If you feed them mostly processed food items, you should also occasionally provide them frozen live food to ensure that they get various nutrients. Popular live food includes brine shrimps and bloodworms. You can also give them grasshoppers, crickets, and fruit flies.


Should feed Jack Dempseys twice a day. You should provide them the amount that they can finish in two to three minutes. Should feed small fish more often. You may need to feed them three times a day so that they grow.


How to Breed the Jack Dempsey Fish?


Breeding Jack Dempsey is not easy. The male and females both should be ready to mate. Sometimes, a male that is ready to mate will harass the female to the point of death. Breeding them involves a lot of luck and patience.


It would help if you kept the water conditions near perfect for encouraging the fish’s breeding. Should keep the water temperature at about 840F (290C). Larger males will be more likely to mate given the right tank conditions.


When breeding Jack Dempsey fish, you should look at the color of the fish. It will give you an indication of the time when they are ready to mate. The fish will turn a dark color when ready to breed. If the male is ready to mate, but the female is not ready for mating, you should keep her in a separate tank. Introduce the female to the male-only when she is ready for a mate.


Consider placing a flat stone inside the aquarium to encourage the pair to breed. The couple will inspect the stone and clean it to prepare for the laying of eggs.


After successful mating, female Jack Dempsey will release about 500 eggs on a flat surface. In case you have not placed a flat stone inside the aquarium, the fish will lay eggs on another flat surface that it finds, such as the walls or substrates.


Eggs will hatch after about three days. Jack Dempsey fish turns out to be surprisingly attentive parents. They will dig holes inside the substrate to protect the fry. The fish will place each fry inside the cave for protection.


Both the male and female will share the duty of protecting the young until they swim freely. The parent fish will even crunch food and feed their young until they are old enough to feed themselves.


A proper tank environment is critical for the successful breeding of Jack Dempsey fish. A low tank environment will create stress, due to which the pair will not likely to mate. They might even start eating the young if not fed properly.


What Are the Care Requirements for the Jack Dempsey Fish?


Keeping the Jack Dempsey fish in a tank requires a lot of care. They can get diseases like most other freshwater fishes. A common problem is a parasitic infection called ich that appears in white spots on the body and fins. You can treat the condition by increasing the temperature to 860F (300C).


Another disease that commonly affects Jack Dempsey is Head and Lateral Line Erosion (HLLE). The disease manifests in the form of a cavity on the head due to poor nutrition. If you notice a pit on the fish’s leader, you should change the diet to ensure that it gets many nutrients.


Similar to other fishes, Jack Dempsey fish is also prone to skin diseases. Skin diseases are majorly caused by a fungal, parasitic, or bacterial infection. You should treat the diseased fish by putting it in a different aquarium and use appropriate treatment measures.


Knowing all the signs of the disease is essential to take measures early to treat the condition. Early identification and treatment will also ensure that the disease doesn’t affect other fishes inside the aquarium. Quarantine of the fish afflicted with an illness is essential so that the condition is not transferred to the other fishes inside the aquarium.


With proper care, Jack Dempsey fish can live for ten years or more. Adequate nutrition is essential to avoid diseases among the fish. The tank should also be kept clean at all times. Water temperature and other tank parameters should also be checked and adjusted if required.


Related Questions about the Jack Dempsey



What are the Different Types of Jack Dempsey?


You can find color variations of the Jack Dempsey fish on the market. Electric blue Jack Dempsey, Gold Jack Dempsey, and pink Jack Dempsey are the standard color variants. These variants are highly sought after by aquarists. But they are generally expensive and hard to find in the market.


How Long Do Jack Dempseys Live?


Jack Dempseys generally live between 8 to 10 years. Some can live for up to 15 years in an established fish tank.


What Lighting is Best for Jack Dempseys?


The natural light is dim in places where the fish is found in the wild. It would help if you tried to mimic the same environment by keeping the tank lights dim most of the time. Floating plants are also recommended as they provide shade inside the aquarium.


Fluorescent lighting is commonly used in most aquariums. But the lighting is not suitable as it highlights the plastic plants, substrates, and elements. The natural colors of the fish are not highlighted. You should go for LED lighting that consumes far less energy and highlight attractive features of the fish. LED aquarium light will also last for a longer time as compared to fluorescent lights.


Where Can I Find a Jack Dempsey Fish for Sale?


You can find a Jack Dempsey for sale at most pet stores. The fish are generally sold for somewhere between $10 and $15. Exotic variants like the electric blue Jack Dempsey are more expensive and hard to find.


Wrapping it All Up: Are Jack Dempseys Ideal for Your 



The Jack Dempsey fish is not right for everyone. Beginner aquarists will have trouble taking care of the fish. The tank parameters should be just right as well; otherwise, the fish may die prematurely. Due to its aggressive nature, you shouldn’t keep it with other species in an aquarium.


Expert aquarists will undoubtedly love the challenge of caring for the Jack Dempsey fish. The efforts will be worth it as the fish has a colorful and exciting personality. The information in this guide can help you take proper care of the fish with a fierce and eclectic demeanor.


Click here to know the 30 most popular Fish for your aquarium.


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