One of the more well-known freshwater cichlids is Jack Dempsey. These tropical fish are so diverse that they come in all shapes, sizes, colors, and personalities. Jack Dempseys are aggressive fish, but with the right guidance, they can thrive in a home aquarium. Here’s everything you need to know about caring for Jack Dempsey cichlids.
Jack Dempsey fish have large oval-like bodies and long fins. Males tend to be bigger and have longer fins. They come in a variety of colors, including gold, blue, or even pink.
Their colors darken when they are mating and lighten when the fish is sick or stressed. Their color also changes based on their age. Young Jack Dempseys are pale with greenish specks. As they age, they develop a purple-grayish color with bright blue or green specks.
What Are Jack Dempsey Fish?
The Jack Dempsey is a species of cichlid fish that is native to freshwater habitats from southern Mexico to Honduras but also introduced elsewhere. Its common name refers to its aggressive nature and strong facial features, likened to that of the famous 1920s boxer Jack Dempsey.
| Jack Dempsey | Quick Info |
|---|---|
| Care Level: | Intermediate |
| Temperament: | Aggressive |
| Color: | Gray with bright specks (green, blue, orange, yellow) |
| Lifespan: | 8-10 Years |
| Size: | 8-12 Inches |
| Best Water Temperature | 22–30 °C (72–86 °F) |
| Diet: | Carnivorous |
| Family: | Cichlidae |
| Minimum Tank Size: | 80 Gallons |
| Tank Set-Up: | Tropical freshwater |
| Compatibility: | Aggressive fish of a similar size |
Jack Dempsey Photo Gallery
Tank Size
Jack Dempsey fish need an 80-gallon tank or bigger to thrive. If you plan to keep one Jack Dempsey, a 55-gallon tank will do. Not only are they large, but they are also territorial. They need lots of space to prevent conflict with other fish.
Minimum tank size: A Jack Dempsey will outgrow a small fish tank. A 55-gallon or larger aquarium is best for one jack Dempsey. So, how many Jack Dempsey in a 55-gallon tank? A 55 gallon should be able to house one Dempsey, but, for a pair of Dempseys, a 100 gallon (378 liters) tank would be best. So, only keep one full-grown Jack Dempsey in a 55-gallon aquarium.
Water Parameters
Jack Dempsey fish live in tropical climates and favor water with a pH of 6-7. Water hardness of 9–20 dGH and a temperature range of 22–30 °C (72–86 °F) is best. Use a heater to keep the water temperature stable.
Best water temp for Jack Dempsey cichlids: 22–30 °C (72–86 °F)
Habitat
Jack Dempseys are tropical freshwater fish that live in slow-moving and murky freshwater. The water in their natural habitat is warm and a bit acidic, with low visibility. The bottom of the water is usually sandy or muddy with rocks and plants.
To replicate their natural environment in an aquarium, choose a sandy substrate, and add some caves so that the Jack Dempsey fish can create mini territories.
Some live plants can be useful, but they may sometimes uproot or damage them. Don’t place bright lights on the tank because Jack Dempsey fish prefer murky water. Be sure to use a filter that creates a light current.
Jack Dempsey Cichlid Size
Adult Jack Dempsey fish grow to between a minimum size of 8 inches and a max size of 12 inches. Males usually reach up to 10 inches in length and females are generally shorter in length than males.
How Long Does It Take A Jack Dempsey Cichlid To Grow?
The usual growth rate for a Jack Dempsey cichlid is around 1.5 years to reach its full size. On average, a Jack Dempsey grows a couple of inches a year. Of course, though they grow pretty fast, it depends on tank footprint, diet, and water quality. Small tanks will make them grow slower.
How Can You Tell A Male Jack Dempsey From A Female?
The easiest way to tell male from female Jack Dempseys is to check their cheeks. Males have bluish spots behind their eyes, with no spots on the lower part near their mouth. Female Jack Dempseys have markings that extend the full length of the cheek with large bright blotches on the lowest part of the cheek.
Female Jack Dempsey
Here is an image of a female Jack Dempsey Cichlid:
Male Jack Dempsey Cichlid
This is a photo of a male Jack Dempsey Cichlid. Notice that there are no blotches of color on the lower side of the face. See another full-grown Jack Dempsey fish (male) in this YouTube video.
Juvenile Jack Dempsey Fish
Here is a photo of a young Jack Dempsey fish:
Jack Dempsey Fish Colors
Jack Dempsey cichlids are usually gray, purple, or deep brown in color. They also have shiny green, gold, or blue blots, and dark streaks on their backs. Males tend to have more blots than females.
Why Do Jack Dempsey Change Colors?
Jack Dempseys communicate through chromatophores – their ‘controllable color cells’. Dark usually indicates aggression and pale means nervous. Most of the time, a Jack Dempsey should be dark, becoming paler only if the water gets dirty or the environment is stressful.
Diet – What Do Jack Dempsey Fish Eat?
Jack Dempsey fish eat anything small enough to fit in their mouths. In the wild, their diet includes frogs, fish, insects, worms, and crustaceans. They also nip at plants from time to time. So, feeding your Jack Dempsey plants like kayle, lettuce, and even plankton from time to time is beneficial.
To ensure that your Jack Dempsey has a balanced diet, feed it Cichlid flakes, pellets, and frozen/live foods. For instance, besides flakes, Jack Dempsey will eat bloodworms or brine shrimps.
If you can, chopped earthworms and small pieces of fish are ideal. If you have access to crickets, grasshoppers, and fruit flies, Jack Dempsey fish will gladly eat these as well.
Best Food For Jack Dempsey Fish
Jack Dempsey fish prefer live food; these are the best options to feed your Jack Dempsey fish:
- Crickets
- Feeder fish
- Small frogs
- Other live foods
Lifespan – How Long Do Jack Dempsey Fish Live?
The average lifespan of Jack Dempsey fish is 8 to 10 years in captivity. With proper care, Jack Dempsey can live beyond over 15 years.
Tank Mates
Aggressive fish don’t have many compatible tank mates. But, there are some safe choices. These are the best Jack Dempsey tank mates:
- Oscar Fish
- Mbuna cichlids
- Angelfish
- Clown Loaches
- Silver Dollars
- Firemouth Cichlids
- Convict Cichlid
- Rainbowfish
- Cave Tetra
- Green Terror
The above tank mates are either of a similar size or have the same aggressive behavior as Jack Dempsey fish. So, they can’t eat each other, and they can all fend for themselves.
If you want to keep only Jack Dempseys in an aquarium, do not keep more than one male in the same tank. Species-only tanks work best with one male and female Jack Dempseys.
Avoid keeping freshwater snails or freshwater shrimp in the same tank as Jack Dempseys as they will attack and eat the smaller crustaceans. Unless, of course, you’re using the crustaceans as feeders. For instance, you can raise ghost shrimp to feed your fish.
Things To Consider
Care
Jack Dempseys are easy to care for once you get used to their aggressive traits. To avoid aggression, make sure that the aquarium dimensions are large and that they are lots of hiding places. Keep the water conditions ideal and make that the fish are well-fed. Jack Dempseys have simple care requirements.
Behavior
Jack Dempsey fish are aggressive. They are not suitable for beginner aquarists to keep. Male Jack Dempseys like to mark territories and will chase away other fish. A tank with lots of cave decorations or live plants for them to hide away and call home helps to reduce conflict.
Breeding
Jack Dempseys get darker in color when they want to mate. Once water conditions are ideal, males will begin to court females. Females give preference to larger males.
Once they mate, a female can produce up to 500 eggs. They deposit eggs on flat surfaces, and the eggs hatch after three days.
Jack Dempsey fish care for their young and will protect them until they mature enough to defend themselves.
But, if the parents are not well-fed or stressed, they can start to eat the young. So, keep an eye on the tank if your Jack Dempsey successfully breeds.
Jack Dempsey Fish Eggs – What Do Jack Dempsey Eggs Look Like?
In the below image, you can see Jack Dempsey fish eggs hatching on a mossy rock. Refer to this YouTube video to see the baby Jack Dempsey fish hatch from their eggs.
Jack Dempseys lay their eggs on rocks, logs, or the glass bottom of an aquarium. Both female and male Jack Dempsey fish help incubate the eggs and guard the fry when they hatch.
How long do Jack Dempsey eggs take to hatch?
With the two parents in the same aquarium, the eggs will hatch in about 3 days. Once the fry hatch from the fish eggs, the adult Jack Dempsey Cichlid (parents) will continue to care for the fry. Water temperature should be between 75–80F (24-27C).
References
- https://biomechanics.ucr.edu/Higham_etal_JEvolBiol.pdf
- Different Fish Types – https://home.adelphi.edu/~ep16926/Fish%20Types%20and%20Requirements.html
- Pashkov, A.N., Zvorykin, D.D. Some morphoecological specific features of cichlasomine Rocio octofasciata (Perciformes, Cichlidae) from the population in Lake Staraya Kuban. J. Ichthyol. 49, 383–389 (2009). https://doi.org/10.1134/S003294520905004X
- Cichlidae – https://animaldiversity.org/site/accounts/information/Cichlidae.html
- Jack Dempsey Fish Food Feeding & Foods – https://www.youtube.com/watch?v=GZkWc65Tfac
- Breeding Jack Dempsey Cichlids | Baby Fish Growing in a Classroom Aquarium – https://www.youtube.com/watch?v=53FSYjLDyiA
- Feeding Jack Dempsey https://www.youtube.com/watch?v=aYCI9CDRvDA – (YouTube Video)
- Why Is My Jack Dempsey Changing Colors? – https://www.myaquariumclub.com/why-is-my-jack-dempsey-changing-colors-728284.html
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