When choosing tank mates, fish pairings are usually classified into three categories: good, OK with caution, and not compatible. Cichlids are often tough fish to pair because most of them are highly aggressive. Platies -- small, easy-going fish -- are in many ways the cichlids' opposites. But carefully chosen cichlids given the right environment can get along with other species like platies in a community tank.
Compatible African Cichlids
A few species of cichlids can live comfortably with platies, but they're exceptions to the rule. The zebra obliquidens (Astatotilapia latifasciata) is minimally aggressive and can thrive in schools of its own species. They grow to about 5 inches long. Jewel cichlids grow to about the same size. They're considered to be one of the least aggressive cichlid species, so you shouldn't keep them with aggressive fish. The compressiceps (Altolamprologus compressiceps) from Lake Tanganyika is nonaggressive and would get along with calm fish like platies. They also grow to about 5 inches long.
African Cichlids That Are OK With Caution
Some cichlids are not overly aggressive and may get along with platies, but pose a greater risk than the tamest cichlids. If these cichlid species show aggression toward your platies you'll need to separate the fish right away. Three examples of less aggressive cichlids are the yellow lab (Labidochromis Caeruleus), the peacock cichlid (Melanochromis Johanni), and the demasoni (Pseudotropheus demasoni). However, demasonis are highly aggressive toward fish that look like themselves. These are all Lake Malawi cichlid species that grow to about 4 inches long. Dwarf African cichlids may also be peaceful enough to live with platies.
Incompatible African Cichlids
Many species of cichlids are highly aggressive and shouldn't be paired with other types of fish. Some African cichlid species to avoid include the bumblebee (Pseudotropheus crabro) and the auratus (Melanochromis auratus), which is considered one of the most aggressive cichlid species. The Livingston (Nimbochromis livingstonii) grows to 8 inches long and is known for eating smaller fish, so it is definitely not a good match for the diminutive platy.
Habitat Considerations
Platies make excellent "beginner fish" because they're hardy and can adapt to different water temperatures and pH levels. Most cichlids are captive-bred and can also adapt to their environment better than their wild-caught counterparts. They need water between 75 and 80 degrees F. Platies do well in water between 65 and 78 degrees F, so water kept at 75 degrees F should appease both species. Changing 25 percent of the water weekly along with a strong filtration system will keep water within the ideal pH range for both fish types -- between 7.5 and 8.
