Was told by someone on another group that my Nimbochromis Venustus was female due to rounder fins, but I did a water change on the 125 gallon and woke up to bright metallic blue on the gill plates and lips, Any ideas? Current size is close to 3.5 to 4 inches if I had to guess. Also has a metallic blue hue to the body. I have had Him/Her for 2 months now. I am going for an all male tank and do not want females for obvious reasons, Any help would be appreciated!