The family Cichlidae or the cichlids is infamous for aggressive, sometimes large fish. But it is a huge family of fish, and contains some small, peaceful species as well. Many of these make great additions to peaceful “community” style aquariums.
The ram (Mikrogeophagus ramirezi) is a small, colorful fish from Brazil. They stay under 2.5 inches, with the female slightly smaller. Several color varieties have been produced by selective breeding. These include the golden ram and various long-finned varieties. The blue ram is the closest to the wildtype coloration. They are small, peaceful and get along well with other fish. They do their best in water with a pH of 6 to 7, and sometimes do poorly in water with a high pH.
The krib (Pelvicachromis pulcher) is named after its old scientific name P. kribensis. People started calling them kribensis or kribs. The scientific name changed, but the common name stuck. These are a small west African river cichlid. They grow to about four inches. They are not particular about water conditions. Like the ram, several color varieties exist, including long-finned and albino varieties.
Apistos are small cichlids from South America. They belong to the genus Apistogramma and are relatives of the ram. They are generally more delicate than the other species here, and require soft, acidic water. They include about a hundred species, including many colorful fish. They also do their best in densely planted aquariums. While small and friendly, they are also expensive and delicate, so a species tank might be the best idea.
The Bolivian ram (Papiliochromis altispinossa ) is another small cichlid from South America. They are related to the more common blue ram. However, they are hardier and slightly larger, as they have not been selectively bred as much as the blue ram. This also means that they are slightly less colorful than the blue ram, but have a kind of rugged charm. The males grow to about 3 inches.