jack dempsey care guide

Jack Dempsey Fish | A Complete Care Guide

Jack Dempsey, one of the most wildly kept cichlids around the globe. This amazing fish is best known for its natural beauty and attractiveness. Aquarists tend to get mesmerized by the spellbinding beauty of this fish.

Jack Dempsey cichlid is notorious for their aggressiveness and territorial behavior towards their companions. Although, this behavior is hard to tackle sometimes and can become quite a trouble for beginners. Still, fish hobbyists never leave any opportunity of keeping this fish.

Regarding their dazzling colors and striking patterns, calling this fish the “jewel of your aquarium” won’t be wrong.

 Let’s dive into the details about this wonderful fish in the following article.

Jack Dempsey: The Famous Aggressive Cichlid

Origin and History

Jack Dempseypopular Central American freshwater fish was named after the heavyweight boxing champion Jack Dempsey. The boxer was known for his aggressive and pitiless nature. The same goes for this aquarium cichlids; Jack Dempseys are quite ruthless and aggressive fish in the aquarium towards other fishes.

Scientific nameRocio octofasciata
Care levelEasy to medium

Jack Dempsey fish originally came from Mexico, Thailand, Hawaii, and Honduras. They are mostly seen around north and central America. Moreover, local breeding mostly occurs in farms around Florida and Australia.

This member of the cichlid family is close in behavior to other cichlids, including Angelfish and Oscar. Jack Dempsey fish can easily survive in warm and high-temperature waters; this fact reveals the true strength and hardiness of this fish. 


This fish is similar to the legendary boxer, not only in behavior but also in appearance. It has strong and bold physical features.

The main reason for the popularity of Jack Dempsey fish is its wide range of bright and attractive colors. Although there are thousands of varieties of this fish, the most common and most loved one is following.

  • Electric blue jack Dempsey
  • Glowing golden
  • Sparkling pink

The body is oval in shape and has flowing long fins. Like the rest of the cichlids, this fish has a thin body, which is the characteristic of other predatory fish.

Moreover, the colors vary individually and with age as well. The juvenile form has paler grey color with sea-green flecks, whereas the adults have vibrant purple color with bright blue flecks.

Furthermore, the male and female forms also differ in colors. The male is brighter in color with long dorsal and anal fins in mature males. Additionally, males have fins with pointed tips, which gives them a more majestic look and support to their bodies.

Electric Blue Jack Dempsey Cichlid

The electric blue jack Dempsey is one of the most beautiful varieties of the jack Dempsey cichlid. The adult electric blue jack Dempsey displays a gorgeous blue tint and on average it reaches a length of 8 inches or 20 cm a little smaller than the original Jack Dempsey. 

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Regarding its aggressive behavior, Jack Dempsey fish is not appropriate for beginners. As they fight and tend to earn the place and it becomes troublesome for beginners to handle.

Males are more aggressive and territorial in nature. Although, this behavior is lessened in densely packed aquariums. The more the competition, the more it becomes difficult it fights for space.

Besides, another way to minimize aggressiveness is to build numerous caves or rocks in the aquarium. This way, more fish will have their territory, and lesser will be the competition.


Jack Dempseys generally have longer bodies and long flowy fins. The male grows larger as compared to females. The average size of a Jack Dempsey fish in adulthood can be 10-15 inches at most.

Building Up Aquarium

Naturally, Jack Dempseys are inhabitants of warm, slow-moving water areas, including rivers, lakes, and canals.

Normally, they prefer slightly acidic to neutral water with mildly elevated water temperature.

In order to mimic their natural habitat, the following measures should be taken.

Tank Size

Providing appropriate space to your fish is the most important step. Regarding their large size and tremendous growth rate, an 80-gallon tank is suitable.

 Moreover, each fish requires a minimum tank size with 55 gallons of space; the more space, the better the growth.

Tank Parameters

When setting up a home aquarium a start by selecting a proper substrate. As per their natural habitat, a soft sandy substrate is the best choice. As they are bottom dwellers; thus, the choice of the substrate is pivotal. A hard gravel substrate can be harmful to your fish.

Temperature72-85-degrees Fahrenheit
Tank size80 gallons
Hardness9-20 dGH
Ammonia level0ppm
Chlorine level0ppm

Selecting an efficient water heater is necessary. Maintaining a temperature between 72-85 degrees is necessary for their growth and survival.

A normal ph between 6-7 and hardness of water between 9-20 dGH is appropriate. A water pump is not needed as the Jack Dempsey habitat slow-moving water; thus, additional water currents are unnecessary.

Adding caves, rocks and crevices can prove beneficial, as it increases the beauty of your tank. Moreover, these things provide proper hideouts for your fish. Adding live plants is optional, as they get well along with plants but plant less aquarium also works well for dempseys.

The last thing is the amount of light you expose your fish to. Try to avoid unnecessary light exposure as it can irritate your fish, and they will try to hide.

Jack Dempsey Tank mates

When it comes to selecting companions for aggressive and territorial fish, care is necessary. Try selecting the tank mates that are equal in size and temperament.

As small fish like tetras or rasboras can be eaten by Jack Dempsey quite easily.

Other shy and timid fish like goldfish can be easily bullied. Snails and shrimps are great mid-day snacks.

Following are the best choices for your Jack Dempseys’ tank mates.

  • Oscar fish
  • Angelfish
  • Clown loaches
  • Silver dollar
  • Blue acara
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These fishes are hardy and strong and as much competitive as your Jack Dempseys. Thus, they will get along well, and there will be lessened competition as tank mates.

Keeping Jack Dempseys Together

If beginners wish to keep this extraordinary fish in-home, keeping a pair of Jack Dempseys is the best choice.

Only one thing to be kept in mind is to avoid keeping more than one male in one aquarium as males don’t tolerate each other.


Feeding a Jack Dempsey is quite easy. As they are carnivores in nature, thus anything meaty will work.

In order to enhance their colors, feed live food and bloodworms. Dried, frozen, or live bloodworms are all appreciated. In the natural environment, the most common food for your Jack Dempsey cichlids are insects, crustaceans, and worms.

Processed food, flakes, and fish pellets are easily available and are good options for your fish. Moreover, bottom sinking pellets are better as your fish can easily consume them.

Snails, brine shrimps, and fruit flies are also gladly consumed by Jack Dempseys. Plants are clearly rejected.

Overfeeding is not a great problem, as they eat lots of food to match their growth. Try feeding them twice a day for almost 2-3 minutes each time. A portion of good and healthy food is essential for their growth and maintenance

Jack Dempsey origin and Care guide

How to Take Care of Jack Dempsey?

Although, keeping a Jack Dempsey alone is not much of a problem. A group of these fish can become a little troublesome. Moreover, keeping other species with this fish can make it impossible for beginners to handle.

There are certain health problems that your Jack Dempsey can commonly encounter.

  1. Firstly, Ich disease or white spot disease is the most common one. This disease is mostly caused by an ecto-parasite called  Ichthyophthirius multifiliis.

    Increasing water temperature is a good solution to overcome this disease.

  2. Another, common disease your Jack Dempsey can encounter is head and line erosion (HLLE). In this disease, there is the formation of pits and cavities over the head of the fish. This is mostly caused by malnutrition.

  3. To avoid the above-mentioned diseases, maintain clean and healthy water for your fish. Clean your tank once every week and replace almost 10-25% of the water every time.

See Our other care guides on Different fish

 How to differentiate Between Male and Female Jack Dempsey?

Although, most of the pet stores can guide you regarding the differences between the two genders. But to ensure the correct choice following differences should be kept in mind.

  1. Firstly, the males are larger as compared to the females, they have longer fins. The males are more vibrant in color, females are rather pale.
  2. Secondly, the males have their fins with pointed edges; whereas, the females have round edges.
  3. Males are more aggressive and competitive and rapidly tend to fight. Females are comparatively peaceful.
  4. Males have large bluish blotches directly behind their eyes, whereas, females have bright blue spots on the lower part of their face and around their mouth.
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How to Breed Jack Dempsey?

Jack Dempseys are pretty easy to breed. In order to ensure perfect breeding and healthy offsprings, purchase a good-looking and healthy pair of fish. It is imperative to provide them with ideal water conditions and a healthy diet for healthy breeding.

  • When the fish is ready to mate, they grow darker in color. Males tend to attract the female, and if the female is unwilling or not ready, the male will annoy the female fish. To avoid this from happening to separate them ASAP.
  • To ensure healthy mating, appropriate water conditions are to be provided. The higher water temperature around 84 degrees is a stimulus for the spawning process.
  • A bred female Jack Dempsey fish can lay up to 500 eggs at a time. The fry is laid on any flat surface available, including walls or decorations.
  • The fry will hatch in the next 3-4 days. The bred male and female build holes in the substrate as a living space for their young ones.

Both parents contribute to taking care of their fry. They provide them with finely ground food. Sometimes, the parents are exposed to some environmental or physical stress. In that case, they might start consuming their own fry. To avoid that, you need to separate them immediately.


As it has been made clear that dempseys are quite easy to breed. Thus, they are fairly reasonable in price as well. A decent specimen with the appropriate size can cost you around 10-15$.

With their tank and other essential requirements included, they can cost up to 35-40$. Dempseys are hardy and easy to take care of but are difficult to keep regarding their competitive nature.


How big do jack Dempseys get?

On average, if kept in the wild male usually reaches a maximum length of 12 inches or 30 cm, while a female gets about 10 inches or 25 cm of maximum length. If kept in a spacious aquarium, the male may reach 10 inches, while the female will get up to about 8 inches long. 

How big do electric blue jack Dempseys get?

At average, an electric blue jack Dempsey can be a little smaller than an ordinary Dempsey and if kept in a roomy aquarium it can reach a length of 8 inches or 20 cm.

How long do jack Dempsey fish live?

8-10 years. A  well kept Jack Dempsey can live up to eight to ten years.


Although not a beginner’s fish, dempseys are still wildly kept around the world. From their natural habitat to their tank condition, from their food to their tankmates and breeding, we tried to guide you about everything regarding Jack Dempsey.

I hope our article helped you a lot and now you are ready to keep them.

Tell us about your experience with this fish in the comment section below.

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