Name: Maylandia callainos
Origin: Lake Malawi (Africa)
I think I have one of these, when in sunlight he looks exactly like this one! He has built a little nest like thing under some rocks I provided for them. He sucked up the gravel and dumped it one rock at a time out of his little cave!
I know I have two of these in my tank cause I work at a local pet store. They do exactly what Eric Brown has posted. They are also kind of territorial and aggressive toward other fish. It's like the little blue fish with a bad attitude.
I bought two of these due to the recommendation of the local pet store owner. Awesome advise. When I bought them they were very young. It's been around 6 weeks, like little babies, boy have they grown! They are so beautiful and irridescent. I am looking into setting up another tank and I can assure you that they will take up residence in the new tank as well!
I have one of these that under my light actually looks purple. He is very active and though he is the smallest fish in my tank, is still somewhat agressive.
I've had a Blue Cobalt in my African Cichlids tank for almost 6 months now. What a beautiful fish! It kind of does its own thing and swims around in the tank. My blue cobalt doesn't bother other fish and it doesn't get bothered by other fishes as well! It has grown from less than 5 cm to 8 cm over the past 6 months. A nice color contrast to my other African Cichlids.
I have one of these fish too, in my cichlid tank. Its tank friends are: one giant green texas, one blood parrot, and one other cichlid, (still trying to figure out what it is). I love them all but this one has the most interesting colors and personality, it is the second smallest, but no one dares pick on him. Lovely fish to watch.