Name: Melanochromis chipokae
Origin: Lake Malawi (Africa)
These fish seem to be difficult to sex. And are extremely aggressive even for African Cichlids. Mine started off Yellow. Then when they established themselves, they turned Purple. I had to separate the larger one.
I have one, had it in a community tank and it changed color to a black and light brown striped fish. Now I moved it into a Cichlid tank and it went back to yellow and black and now 2 months later it is dark black and dark brown striped, is about 5 cm long and attacks my texas cichlid who is about 16 cm long. Little guy has guts, fun to watch.
Melanochromis chipokae is one of the most aggressive mbuna (rockdwelling) species. They are also one of the larger species, and are unsuitable for all but the largest tanks. M. chipokae is often mistaken for M. auratus, due to similar coloration. Though M. chipokae is a mbuna, it isn't vegetarian. In nature, it eats invertebrates and small fishes (predatory). I don't recommend this species for novice cichlid keepers.
I have 3 M. chipokae, and they are easily the most aggressive mbuna along with Melanochromis sp. 1 and 2, the "giant pike auratus". Very mean, I've lost many fish to my other mbuna, but when I introduced my first male chipokae, all the other mbuna were quickly killed along with some heavy duty C.A. cichlids, a couple natives (sunfish and bass), and pretty much anything which wasn't more aggressive than it. They are specialized predators from the long snouted Melanochromis melanopterus subgroup, and as such, have fewer larger teeth than their smaller, comparatively peaceful relatives of the auratus subgroup.
The color changes mentioned in other posts are typical of the male M. chipokae. They will all start out yellow, with dominant males turning a purplish black. If there is more than one male in a group, only one (the dominant male) will make the complete color change. Sub dominant males will retain the juvenile color or have a slightly dark "tinge". If a male in dominant color is put into a group where he is no longer dominant he will revert to the juvenile yellow color and any sub dominant males in his old group will vie for position with the new dominant male taking on the male color. That is...IF they all survive this vying for position. These are extremely aggressive fish, even for African Cichlids. Also, to easily tell them apart from M. auratus, look at the tails. The M. auratus tail retains the body striping with half solid and half striped. The M. chipokae tail is all striped. They are often mislabeled in fish stores, sometimes mixed in a tank all labeled as one or the other.
Another way to differentiate between chipokae and auratus is that the chipokae has a black outline around its lips.