Herotilapia multispinosa (previously: Archocentrus multispinosus) also known as the rainbow cichlid is a Central American freshwater fish of the cichlid family. It is found on the Atlantic slope of Honduras, Nicaragua, and Costa Rica from Patuca River (Honduras) south to Matina River (Costa Rica), and on the Pacific slope of Nicaragua and Costa Rica from Guasaule River south to Tempisque River. Specimens are also reported from the Choluteca River on the Pacific side of Honduras.[1] This species is found in lakes and swamps with muddy bottoms, where it uses its specialized teeth and only 3.5% jaw protrusion to feed mostly on algae.[2] It is commercially important as an aquarium fish. The rainbow cichlid prefers a pH range of 7.0–8.0, water hardness of 9-20 dGH and a temperature range of 21–36 °C.
The rainbow cichlid was first described in 1867 by Albert Günther and was then placed in the genus Heros, a synonym of Cichlasoma. In 1903, it was removed from the Cichlasoma and placed in its own new genus Herotilapia, solely on the basis of its unique tricuspid teeth, an adaptation to eat filamentous algae. It was then called Herotilapia multispinosa.[1] Herotilapia had been considered to be closely related to, or even synonymous with, the genus Archocentrus but DNA analysis by Oldřich Říčan, et al. demonstrated that the two genera are not very closely related.[3] Rather, the closest relatives to Herotilapia are Tomocichla, Rocio, Astatheros and Cribroheros, of which Rocio (including the Jack Dempsey) has the most similar morphology.[3]
The rainbow cichlid can reach 12–15 cm (4.7" - 6") in length, but most adults are around 7–8 cm. The fish is generally yellow, with hints of reds and browns. A line of black central spots runs from the eye to the base of the tail. As an individual's mood and environment changes, it can change its coloration between dark brown and bright yellow, and can either connect the line of spots into a black horizontal stripe, or extend them into vertical stripes that span across the top and front of the fish. These color changes take place over the course of a few seconds, which is unusual in freshwater fish. There is no evidence that rainbow cichlids exhibit sexual dimorphism.
This cichlid is native to both the Atlantic and Pacific slopes of Central America, ranging from Costa Rica to Honduras and Nicaragua. It is most commonly found in turbid and shallow waters such as the weedy margins of lakes and streams, or small ponds that are periodically flooded by nearby rivers. An introduced population has also established itself in a hot spring at Hévíz, Hungary.
The rainbow cichlid is an omnivore. In the wild, it mostly eats flocculent detritus, with a preference for filamentous algae, simple algae, and diatoms.[4] It can also prey on smaller fish and insects. In captivity, it readily consumes commercial flakes or pellets.
This cichlid is a pair-bonded substrate brooder, meaning the male and female mate monogamously (at least for the reproductive season) and the eggs are laid on a substrate to which they stick, rather than brooded inside the mouth.