The Rainbow cichlid (scientific: Archocentrus multispinosus) is a South America cichlid, member of the cichlid group commonly known as dwarfs, due to their small size. The species reaches a maximum size of 6 inches (15 cm), however in aquariums its length is usually around 3-4 inches (7-10 cm). It is a beautiful fish species, with colors ranging from lemon yellow to gold and a distinct horizontal black line that crosses their body from the eyes to the caudal fin1. Its colors change according to its mood and get more intense during the breeding period while the tips of some of its fins turn into a light blue color. There is no great sexual dimorphism2 except for size, as males are usually slightly bigger.
This dwarf cichlid is commonly encountered in rivers with muddy and turbid waters and will live happy in tanks with a minimum size of 50 gallons (180 L). The bottom should be filled with fine gravel, while hideouts such as rocks and pots are essential as this species loves hiding in small places. Moreover, roots and plants are highly recommended in order to create similar environment to the cichlid’s natural habitat. The ph should be kept neutral (7), dH should be maintained around 5-10 dH and temperature around 79-81 °F (21-36°F).
Although the Rainbow cichlid is very peaceful, it is territorial and can get aggressive especially during the breeding season. Nonetheless, its low profile temperament makes it an ideal companion to medium sized cichlid species such as convict and parrot cichlids. Once again, in such communities providing shelter by adding rocks and empty pots is essential in order to keep the aggressiveness to a low level. In its natural environment the rainbow cichlid is a herbivore and it has actually developed a specialized mouth to scrape algae from the rocks. However in aquariums the species can live on a variety of food types, including pellets, flakes and frozen food such as earthworms, provided that food based in phytoplankton or vegetables is added on its diet as a supplement.
Breeding of the Rainbow cichlid is very interesting procedure, as in contrast to most cichlids, it does not form harems and is not a mouth brooder. Instead, male and female individuals form pairs that stay together at least for a reproductive season and males are actively involved in the various procedures of the parental care. Breeding starts with the male claiming a territory in a particular spot, usually among roots and rocks. After a bonding procedure, the female releases around 600-1000 eggs on the ground, where the male fertilizes them with its sperm. Almost immediately after fertilization, the pair engages in a behavior known as “fanning” which consists of gentle circulatory movements of the tail and fins above the eggs in order to provide them with oxygen.
Sometimes, the female excludes the male from this procedure, however the latter has the responsibility to guard the eggs and can get really aggressive with other fish if they approach its territory. When the territories of two rainbow cichlids are nearby, males exhibit a very interesting behavior: they stay in the borders of their territories and swim forward and backward, exchanging charges and retreats, never trespassing the boundaries.
Young fries will hatch within 2-4 days and will be transferred by the parents to a different place, most commonly to a vertical surface, within their territory. Both male and female will participate in the procedure, taking a small number of fries into their mouth and spitting them gently in their new spot. Fries will remain stationary, adhering to the surface by using mucus produced by special cells on the top of their heads. The “fanning” and guarding behavior continues for a few days until the fries become free swimming. Despite being able to swim, they will remain in a group guarded by the parents for a few weeks. This parental care lasts for a total of 4-5 weeks, offering spectacular behaviors for the aquarist to observe.
1 Caudal fin: the tail
2 Sexual dimorphism: The existence of morphological differences between males and females.
Axelrod H.R. 1993. The Most Complete Colored Lexicon of Cichlids
Ulrich Glaser, Wolfgang Glaser. 1996. AQUALOG: South American Cichlids I-III