Can Firemouth cichlid Live With Jack Dempsey?

The firemouth's own profile allows similarly sized Central American cichlids given enough room, and the Jack Dempsey is from the same region, though at 20 cm against the firemouth's 12 it is the more dominant fish of the pair rather than a true match in size. The firemouth is also the milder tempered of the two most of the year, aggressive mainly at breeding time, while the Jack Dempsey carries the harder edge generally.

Both take a wide band, 20 to 30 °C and pH 6.5 to 8, so water gives no trouble.

Give the firemouth's smaller size room to matter: a tank at the Jack Dempsey's 243 litre minimum or bigger, with enough floor area and hardscape for two separate territories, plus a flat stone each species can claim for spawning. In anything tighter, expect the Jack Dempsey to dominate the space and the firemouth to spend its time avoiding it rather than settling in.