Jack Dempsey | All about habitat, size, colour, food and live

Jack Dempsey | All about habitat, size, colour, food and live

Jack Dempsey (Rocio octofasciata, formerly called Cichalasoma octofasciatum ) is one of the most widespread aquarium fish in North and Central America.

Due to the aggressiveness that this fish has with the rest of aquarium companions, aquarists in the United States gave him the nickname of Jack Dempsey, by the popular professional boxer.

We have to recognize that from pescadeacuario10.com we feel predilection for this beautiful and peculiar aquatic animal. Let’s begin to see everything necessary for the care and maintenance of the boxer fish in our aquarium!

Natural habitat

This species was called by the name of dew, the name of the wife of its discoverer. In Castilian Rocío means drops of water on a surface which mimics the drops of colors that these fish have on their body.

The scientific name of this fish ” octofasciata ” comes from the Latin words “octo” (eight) and ” fascia” (stripes or belt) which means 8 stripes.

The Jack Dempsey fish is native to the waters of the Atlantic coast of Central America . It inhabits the surroundings of the Ulúa River in Honduras and extends to the Papaloapan River in southern Mexico.

We can also find this type of fish in the waters of Guatemala, specifically in the Belize region. The Jack Dempsey fish came from the hand of man to the waters of the southern United States (in the state of Florida and in areas near the Gulf of Mexico) as well as in waters of Thailand.

It usually inhabits shallow rivers with clean waters , as well as small lakes, although it is not uncommon to find them in turbulent waters with muddy bottoms. They like to live in waters full of plants with muddy bottom or sand.

How big is?

Rocio octofasciata is a species of Cichlasoma that reaches a fairly large size. The males can measure up to 21 cm long and the females, although they are a little smaller, measure up to 17 cm long.

However, in our aquariums the male fish will not tell me more than 15 cm long and the female 12 cm.

What color is it?

The Jack Dempsey is a dark greenish color . When this fish is angry or during its spawning period it becomes much darker until it becomes almost black. There are some parts of your body such as its fins or gills which, upon exposure to light, can acquire a bluish or gold color.

Females have a less bright color . The fingerlings del Rocio octofasciata have their body covered with stripes , from 8 to 11, and have lighter shades that adult s. In adults they have stripes on the forehead like the back and abdomen.

There is a type of this fish called “Jack Dempsey blue” compared to dew this normal fasciata has a much brighter coloration, smaller body and has a less aggressive character.

This species is unusual to see and has emerged from the Jack Dempsey with other cichlid species.

What is the food of the Jack Dempsey?

In its natural habitat it is a predator and feeds on live foods such as shrimp, lyophilized blood worms, frozen fish, or small pieces of seafood. These fish are omnivorous so you also have to feed them with vegetables such as lettuce, cabbage or cabbage.

We must not forget that before giving them these foods we must boil them first to eliminate the possible bacteria they contain .

The frequency with which we must supply the food must be once a day and take the right measure so that there is no waste in the water. The general rule to know the amount of food to be supplied is that which is able to eat our animal for 3 minutes. One of the main problems that aquarium fish suffer is overfeeding so we must be measured at the time of feed them.

What capacity should my aquarium have?

Thinking about getting fish for this species, we must have at least a 200-liter aquarium for a pair of Dempseys. The aggressiveness of this species depends largely on the size of the tank in which we place them. In an aquarium with a capacity of less than 200 liters we can not put fish that are of different species and even when they are in breeding season if we do not separate the fry they will end up eating them.

If despite having an aquarium of these dimensions and see that they fight frequently we recommend separating them immediately. If it does not end up killing.

What maintenance does the tank have to have?

Like most cichlids in Central America, Rocío octofasciata does not need any special care to live in the aquarium. The basic care you need is to have clean water with balanced levels of pH, ammonia and nitrites, as well as having a water filter that removes impurities from it.

If you introduce young Jack Dempsey remember that if you do not renew some of the water and it is full of waste, it is very likely that it will not reach more than 4 years of age. The fish when it becomes an adult will suffer from diseases such as hexamithiasis and other diseases.

How long can my fish live?

If you maintain all the necessary conditions for your fish to have a healthy life, it can live more than 10 years .

At what temperature should you have the water?

The optimum water temperature for Jack Dempsey is 26 to 28 ° C .

The temperature cannot be lower than 24º Celsius . In fact, you will realize that if the temperature falls below that scale, the fish will remain close to the heater.

Scientific nameRocio octofasciata, Cichlasoma octofasciatum
Common nameJack Dempsey, Electric Blue Jack Dempsey
Tank size200 liters
Temperature75-81 ° F (24-27 ° C)
size17 cm (6.69 inches)

How can I differentiate the male from the female?

The male is larger and has more vivid hues . You should keep in mind that when you buy a fish of this species with less than 4 months that the female is larger than the male . That is why when they are young it is very difficult to differentiate them.

Another aspect that we can consider to differentiate sex is behavior . The males from their early months, show a territorial behavior point do not like other fish swim with them.

The dorsal fin in males is pointed while the female is rounded . This happens in the first months of life although when they reach the mature age both genders tend to have the pointed fin.

What partners can you have in the aquarium?

In tanks with large capacity, Rocío octofasciata, does not show such aggressive behavior as it does in small tanks. We can put it in the aquarium with other fish of cichlid species of equal or greater size . Never smaller, since the outcome is likely to end the death of one of your fish.

You can make it compatible with:

  • Hot water piranhas
  • Disco fish and its different varieties
  • The great Aquarius Oscar
  • Emperor Angel Fish

What we should never do is put Jack Dempsey fish with small fish as they will eat them.


At what age do they begin to raise?

In their natural habitat these fish begin to reproduce at 12 months of age . In the aquariums we can start the reproductive season from 6 months . We do have couples in the same aquarium that they form partners themselves.

If you want to form pairs to reproduce, I have to tell you that this is one of the most problematic aspects of Jack Dempsey’s breeding. Males are quite demanding when choosing their partner . What is usually done is to introduce several females with a male and that is chosen with any mate.

If we focus on it in this way we minimize the conflicts within the aquarium and we will inhabit that the female fish, normally smaller and weaker, do not suffer any type of damage.

What is the female’s behavior during mating ?

When the pairs are being made to reproduce, the females show an aggressive character . If you have several females inside the aquarium you will realize that the most dominant of the group tries to attack their tank mates. Once the pair has been created for reproduction it is recommended to remove all the fish that do not compose it.

How is spawning carried out?

Spawning will take place on the substrate and the accessories that we have in the aquarium. They will spread their eggs throughout the tank . It is recommended to acquire a separate tank from the main one for the spawning of the Jack Dempsey. If you have a catfish,  I recommend that you take it out of the aquarium during this period since it can eat the eggs of the spawning.

Once the spawning has been done, the eggs will grow for 3 to 6 days, depending on the water temperature and its parameters. The day before the eggs hatch, the Dempseys will cover the eggs with the sutrate. This can confuse us and we may think that the fish has eaten its children. In the first days of the fry’s life, the mother will feed the little ones.

The fry begin feeding themselves 4 days after birth. They will start eating shrimp and dry food. They will tend to hide in aquarium plants .

Parents will share reproductive tasks . The female will take care of the eggs and feed her little ones and the males to keep their territory . These tasks are usually one of the reasons why Dempsey couples tend to fight since females during this period tend to consider that the male is not saving enough territory and fear that other fish can eat their eggs.

That is why it is best that the males be separated just after the spawning has ended, yes, in case of keeping other fish in the aquarium.

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