Description
Remarks: The rainbow humphead cichlid (Gymnogeophagus lipokarenos) is a smaller eartheater very rarely seen within the hobby. Such rarity is driven not by lack of interest as many collectors seek them out for their beautiful coloration and impressive nuchal humps present on mature males. Juvenile rainbow humphead cichlids are mostly muted tan in color, but mature fish shine with a rainbow of red, yellow, orange, blue, and green hues giving rise to their common name. Such coloration is most vibrant in dominant males while females and lesser dominant males are more muted.
As mentioned previously, the rarity of the rainbow humphead cichlid in home aquariums is not due to a lack of demand, but rather a lack of availability. In the wild, this species is known to only occur in the Río Uruguay and the Río Negro within Brazil and Argentina. Combine the limited native range with the fact many other similar looking species of Gymnogeophagus can also be found in these areas, and the result is that true Gymnogeophagus lipokarenos are almost never exported. Captive breeding has proven to be fairly challenging as well since this species requires conditions to be just right to induce spawning.
Rainbow humphead cichlids are not very picky eaters, remain a manageable size, and are very docile even toward smaller fish and conspecifics, but it is not a good choice for those unfamiliar with Gymnogeophagus. This is due to their requirement of having pristine water conditions and an annual cooling period that they would undergo within their natural habitats. Frequent water changes alongside soft, acidic water parameters are a must if one wants to avoid illness. While they will tolerate warmer temperatures for short periods, the health of rainbow humphead cichlids will gradually decline over time if they are not given an annual period of lower temperatures between 57-65 °F for at least a month or so. Make sure the temperature change is done gradually over the course of at least a few days to a few weeks to avoid temperature shock.
Not only does this cool period improve the health of your rainbow humphead cichlids, but it is also required to induce spawning. If looking to undertake the challenge of breeding, you can increase your chances of successful spawns if this cool period is induced during what would be the winter months in South America, June-August. When ready to spawn, a pair will select a smooth surface such as a stone that they clean before attaching their eggs. Both the male and female will guard the eggs until they hatch, upon which the female will take the newborn fry into her mouth. Only the female will continue to care for the fry until they are large enough to fend for themselves.
Like all eartheaters, rainbow humphead cichlids require a sandy substrate due to their earth-eating habits. They sift mouthfuls of sand through their gills, pulling out bits of food to eat. Gravel presents a very high probability of choking or refusing to eat. Also like their close relatives, these fish do best in groups of 4 or more but can also do well in single male and female pairs. Due to their smaller size, adult can be kept in an aquarium as small as 40 gallons if kept as a single, breeding pair, but 75 gallons or more is recommended if they are to be kept with other fish. Whether undertaking the challenge of breeding this species or looking to keep a cool-water community tank, rainbow humphead cichlids are a joy to keep.
