Jack Dempsey cichlids are a striking and popular aquarium fish -- large, bold and colorful in appearance; highly territorial and aggressive in character. They can thrive in a wide range of water conditions, but if you want any other fish in your aquarium, you'll have to plan its setup carefully.
As adults, Jack Dempsey cichlids will be between 8 and 12 inches long. Their large size, combined with their aggressive territoriality, means they must have a large amount of space. A lone Jack Dempsey can be kept in a 30-gallon aquarium, although 45 gallons or larger is preferable. A pair of Jack Dempseys will need at least a 60-gallon aquarium.
If the other fish are of equal size and aggression, Jack Dempsey cichlids can sometimes be kept in a community aquarium. They often can live in peace with aggressive catfish from the Loricariidae and Synodotis families, as well as tinfoil barbs or silver dollar fish. Other Middle American cichlids also seem to get along well with the Jack Dempsey cichlid. When considering a community aquarium, remember that the aquarium size must increase for each additional fish. Breeding pairs of Jack Dempsey cichlids are extremely aggressive during spawning, blocking other fish from entering their territory, so an aquarium that's at least 6 feet long will be required.
Jack Dempsey cichlids are carnivores, and they need a steady diet of meaty foods. These highly nutritious foods can quickly foul their water. The aquarium setup must include a good filtration system, suitable for the size of your aquarium.
Digging in mud and sand is a favored pastime of Jack Dempsey cichlids, so for starters, spread a thick, soft, loose substrate such as aquarium sand on the bottom of the aquarium. An inch or two of substrate thickness -- more, if you choose -- will allow the fish to dig happily. Because Jack Dempsey cichlids are territorial and aggressive, it is important to place objects such as flat rocks, driftwood, aquarium caves and overturned flower pots on the substrate to help mark territorial boundaries. The flat rocks are essential during breeding, as the fish will lay their eggs there. The caves and overturned flowerpots will serve as hiding places, letting the fish feel secure. Jack Dempsey cichlids will uproot live plants, but you can add floating plants to the aquarium. These floating plants also will shelter the fish, making it feel safer.
Jack Dempsey cichlids can adapt to a wide range of water temperatures, from 70 to 86 degrees Fahrenheit. You can raise the temperature to the warmer end of this range to make the fish more active and help induce breeding. Unfortunately, the more active fish is the more aggressive he will be. Temperatures between 72 and 78 degrees are ideal for Jack Dempseys; at these temperatures the fish are less active and their aggression is more manageable. Guard against dramatic temperature fluctuations. Use an aquarium heater to maintain a stable temperature.
Water pH Levels
For health, all fish require specific pH levels for the water they swim in. For Jack Dempsey cichlids, aquarium water with a pH between 7.0 and 8.0 is acceptable, but a pH between 7.2 and 7.8 is ideal. Use a water-testing kit to measure the pH of aquarium water. Adjust the pH with aquarium additives. These supplies are commercially available in pet stores and wherever fish and aquarium supplies are sold.