Animal-World > Aquarium Tropical Fish > Cichlids > Jack Dempsey Fish

Jack Dempsey

Family: CichlidaeCichlasoma octofasciatumPhoto © Animal-World: Courtesy David Brough

   The Jack Dempsey is one of the most interesting and beautiful of the American cichlids!

   A mature Jack Dempsey displays magnificent color, covered with light blue spangley spots all over its body (the female has fewer spots). The male also has bright red edges on its dorsal and anal fins. This is a beautiful fish, but It takes over a year for it to develop full coloration. Today there are some captive bred color varieties with one of the most notable being the Electric Blue Jack Dempsey.

   When first introduced to the aquarium hobby, this fish was considered quite ferocious. It was named after "Jack Dempsey" the 1919 Heavyweight Boxing Champion of the World. Although it is rather aggressive it is not nearly as combative or aggressive as some of the cichlids later introduced, such as the Red Devil.

   The JacK Dempsey is a very attractive show type fish, and will do well if provided with adequate space and compatible tankmates. It likes a tank bottom of fine sand, plenty of hiding places among rocks and wood, and a cover of floating plants. They do burrow and will eat the plants. They are one of the easiest cichlids to get to spawn, though when kept in pairs they can become territorial, intolerant, and biters. The Jack Dempsey is easiest to keep either singly or in large groups.

For more Information on keeping this fish see:
Guide to a Happy, Healthy Freshwater Aquarium

Distribution:    The Jack Dempsey was described by Regan in 1903. They are found in North and Central America; Southern Mexico, Guatemala, Yucatan, and Honduras. They inhabit bogs and other slow moving, swampy warm waters, living among weedy areas with sandy or muddy bottoms. They feed on worms, crustaceans, insects and fish.

Status:    This species is not listed on the IUCN Red List.

Description:    The body of the Jack Dempsey is stocky and compact. Adults are striking colored having a dark purple-gray background contrasted with brilliant iridescent blue, green, and gold flecks. Males develop long pointed dorsal and anal fins and may also have a round black spot in the center of the body and at the base of the tail. Juveniles are less brilliant, having light gray or tan background with faint turquoise flecks. If stressed or moody these fish can exhibit great color change in the aquarium, and also with age. Stressed fish will be lighter and their spots will be less striking.

Size - Weight:    These fish get up to 8 inches (20 cm).

Care and feeding:    Since they are omnivorous, the Jack Dempsey will generally eat all kinds of live, fresh, and flake or pelleted foods. They get quite large so they should be fed a high quality pelleted food and large chunk foods such as meat or fish.
   A minimum 50 gallon aquarium is suggested for a a single fish, though a larger tank would be needed if keeping more. They need good water movement along with strong and efficient filtration. Provide a bottom of fine sand and plenty of hiding places among rocks and wood. Plants are appreciated but should be hardy, such as Sagittaria. Place the plants around the inside perimeter leaving an open area in the center for swimming. The plants should be potted to protect the roots.
   The Jack Dempsey is a rewarding specimen for the aquarist as it is moderately easy to keep as long as the aquarium is maintained. They are subject to infections as well as other diseases that ail all freshwater fish. To help prevent the notorious 'Hole-in-the-Head' disease (HLLE - Head and Lateral Line Disease) that large cichlids are prone to, do water changes of 20 to 25% a week, depending on bio load

Water Region: Top, Middle, Bottom:    These fish will swim in all areas of the aquarium.

Acceptable Water Conditions:   Although the Jack Dempsey can tolerate a fairly wide range of conditions, it has been suggested that warmer temperatures lead to more aggression in this fish. Many aquarists will keep the maximum aquarium temperature below 78° F (26° C) to help reduce antagonism.
   Hardness: 8-12° dGH
   Ph: 6.5-7.0
   Temperature: 72 - 86° F (22 - 30° C)

Social Behaviors:    The Jack Dempsey is not considered a good community fish as they get territorial, especially against its own kind and similar species. They also can get more territorial as they get older and so may need to be kept individually in a species tank. If keeping more than one, it is easier and safer for them to keep them in large groups rather than in pairs.

Sexual Differences:    The male has a longer and more pointed dorsal fin than the female. The male may also have a round black spot in the center of the body and at the base of the tail. The female has fewer spots than the male.

Breeding/Reproduction:    Jack Dempsey's are egg layers. The female will lay 500-800 eggs on carefully cleaned rocks. They form a nuclear family. The fry are kept in pits and are guarded by both the male and female in the manner of "monogamous cichlid" breeders. See the description of how to breed these fish in Breeding Freshwater Fish.

Availability:    The Jack Dempsey is readily available available both online and in fish stores and are inexpensive, starting at about $4.00 USD.

Author: David Brough, CFS

Lastest Comments on Jack Dempsey Fish View all 67 comments on Jack Dempsey Fish Add Your Comment

docpat - 2006-06-26 I purchased a two inch a pair of Jacks from the local pet shop. At first they got along well until one began growing significantly larger than the other. I was pretty sure they were a pair when I bought them. The larger one began his mating dance, shuddering and shaking around her, but she was playing hard to get. Finally he began chasing her to the point that one day she was just laying beaten and battered, fins missing on the top of the tank behind the heater. I took her out and nursed her back to health in a small two and a half gallon hospital tank for about a month. I then placed her tank directly in front of his thirty gallon. They saw each other and began following each other back and forth. I let this go on for two weeks. One day I put a piece of paper between the tanks blocking his view of her. He got very upset and was obvoiusly looking for her. After two days I put her in his tank and he began mating behavior again. By the third day he began chasing her around the tank, so I took her out and placed her in the small tank within his view again for a week. Then I reintroduced them. Five days later she laid several hundred eggs on top of and inside of a flower pot and the two of them now swim side by side when she's not fanning and guarding the eggs. I'm not sure when they will hatch, but it has been a real fun adventure to say the least. I have had FW, SW and reef tanks for forty years, but this is the first time I intentially manipulated breeding. Can't wait for the sequel. Click For Replies (3) Kathryn - 2011-04-06 Got a question. When she was laying the eggs and prepairing to do so, did she turn a VERY dark color--almost black, while she was hiding in her area she chose for the laying? Ours is almost completely black. She has been in her hiding spot for about a week or so. Is this all normal? 'Jackie Miller-McGraw - 2011-06-22 Katheryn... mine is doing the same but has tried to kill the male now!!!!??? has yours been aggressive to your male? Joyce - 2012-02-03 My female turns black every time she lays eggs and stays that way until the fry are about 3 to 4 weeks old. They she returns to her normal coloring. I have read that is it due to stress. Reply

Marjorie - 2011-04-05 I have a female jack dempsey and a male j.d. I have had them for over a year now. They have paired up but have not laid eggs yet. I feed them pellets and other frozen foods and worms sometimes. They are in a 55 gallon tank. I also put a mirror on the side of the tank but they have not spawned yet. What am I not doing right? I also put a slate in with them can you give me some advice? Thank you. Click For Replies (3) Anonymous - 2011-06-23 The jacks are really shy they need all the privcy they can get. You may need to cover the front of the tank. Anonymous - 2012-01-22 Turning up the heat a few degrees can help. Joyce Johnson - 2012-02-03 I have a pair of Jack dempseys is the second pair I have had, the first many years ago. Both have readily spawned and reared fry. Are you sure you have a male and a female? Second, I always supply cave areas for my J39;s so if they want to hide they can, and usually it is in the provided cave area where they spawn, bringing the fry out to deposit in one of numerous pits they have made. I keep the temp at 78 and ph at 7.0. Filtration is both biological and chemical (charcoal). It sounds as if feed is similar to you, except I add the algae wafers that they sell for plecos. Good luck! JDs are awesome parents and it is fascinating to watch them care for they young. Reply

sabrina - 2011-11-19 Hi, Has anyone ever heard of a bright red Jack Dempsey? I just got one and I have been unable to find information about about him/her. thanks, =) Click For Replies (1) Brandon Smith - 2012-01-05 Just a very neat JD variant :) Reply

Robin - 2011-02-07 I recently lost two Tinfoil Barbs in my 55 gallon tank. Now I have my one Jack Dempsey. He's 5 years old and full grown. I would like to add a fish or two. What would be the best fish to add and hope they get along? Click For Replies (3) Anonymous - 2011-06-23 My oscar and 3 jacks do fine as long as you keep plenty of feeders. jace - 2011-09-25 I have 2 mating pairs of jack dempseys and 2 fluebonis I think they're called and a bunch of other fish and they all do fine I also had oscars too and they did excellent. samiran roy,india - 2011-11-24 Convict cichlids and oscars do fine with JD's Reply

mike - 2011-08-09 I have a male and female blue gene jack dempsey there about a year or so old, I had got them from a friend who was going to flush them(or try to they are huge). I was wondering how do i get them to breed? Any help would do wonders. I also have a proven pair of red devils that I wanna figure out how to hatch there eggs myself. Click For Replies (1) Charlie Roche - 2011-08-10 I really don't understand the question. How would you attmept to hatch eggs? Found something that you will probably understand but I don't. It says " You can remove the eggs and use a slow airstone as a surrogate mother. The eggs need a slow flow of water near them for the best hatching rate. Most people consider it much more enjoyable (though less predictable) to watch the parents tend the eggs and herd the fry around". It can be done so look up things like artificial incubation fresh water fish, using surragate to hatch eggs etc. That should help. Also, breeding conditions??? Article on Animal World regarding breeding fresh water fish Link is http://animal-world.com/encyclo/fresh/information/breeding_freshwater_fish.htm#cichlids I had circhlids and they would pair off and make all thse little caves using gravel, stones, plants whatever. Then they would just sit. I would then rearrage the tank cuz I thought they were bored. Well almost 35 years have gone by and I have been told that i was supposed to do that. I don't know but he breeds cichlids. Do they need to create a comfortable home? Mine did breed and then I had a whole mess of babies. Reply

Anonymous - 2011-06-23 My 5 inch oscar and 3 jacks which are 2 inches and 2 are maybe 1inch an half do well. I had a red tail shark at one time but moved him to his own tank. The 3 jacks an oscar live well in a 55 tank for the moment as long as you keep plenty of feeders roseies on hand. Ron my oscar can get chassy. But I move things around when i see him acting out. Reply

Add your comment!

View all 67 comments on Jack Dempsey Fish

Back to Cichlids