Ok, that's a small tank. That's the 63 litre tank, or 16.6 US gallons. You really can't even keep the one pair of cyanheorhabdos in there. You would be better off getting dwarf cichlids if you really want to keep cichlids in that tank. Melanochromis are highly aggressive and need space. Bare minimum for them would be a 50 gallon (189 litre) tank, and personally I wouldn't go any less than a 90 gallon (340 litre) for full grown specimens with lots of other cichlids in there as well. I've kept Melanochromis in 90g tanks and I could only keep one male plus some females in there as the male tried to kill off all other males of his species. Other people may have gotten better results in a tank that size, but it is something to think about.
