first of all you do have mbuna. the blue fish, does he look like the red zebras only blue? if so, he is a cobalt blue zebra. mbuna are very aggressive fish, the most aggressive of all being the auratus and chippokae. they like to have harems when mating. one way to keep down the aggression levels is to have three females for every male. the male will become extremely aggressive when mating and will kill any and all unwilling females. the best way to tell if you have the proper ratio of males and females is to vent the fish. one way to guesstimate is by the egg spotts. the egg spots or dummy spots are on the anal fin. one for males and several for females. the chippokae and kenyi are the easiest to sex. the female chippo is yellow and black striped vertically and the male is black and blue vertically striped. the female kenyi is black and blue horizontally striped and the male is a yellow gold color. the fry are born with the same color as the females and will change color when maturing. subdominant males will however retain the juvenile coloring to protect themselves from being killed by a dominant male. they are extremely territorial and the alpha male will rule the tank from a center point. they like to dig so undergravel filters are not a good choice for these types of fish. they are mouthbrooders, meaning the female will lay the eggs, the male will pass over and fertilize the eggs and then the female will scoop up the fertilized eggs into her mouth. she will hold the eggs until the fry are freeswimming. until the eggs hatch she will tumble the eggs around in her mouth. a female usually holds the eggs for three weeks. it is best to seperate the females when they are holding. she generally will not eat, although some females will eat during this time. she also is not able to protect herself so it is best to isolate her till she spits out the fry and let her recover for a few days returning her to the community tank.
mbuna are best fed spirulina, flake foods and blanched veggies. they can be fed protein but it does need to be kept to a minimum. at the most a biweekly, but preferably once a week basis. too much protein in an africans diet will cause a condition referred to as malawi bloat. basically it is the fish is constipated from high amounts of protein. bloat can cause fish loss though. cucumbers, zucchini, shelled peas, broccoli are good choices for food.
when i had my mbunas i fed them three times a day. flake in the am, veggies at noon rotating them so as not to give the same thing twice in a row and emerald green frozen food at night. i thawed the emerald green in tank water and then dumped it into the tank. they loved the stuff!
malawis will show their colors and fight with themselves for practice. it is not uncommon to see them open mouth trying to attack their reflections or other fish in a tank next to them. the black background probably allows them to get a better reflection of themselves. they will also show their colors when mating or trying to ward off aggressors. when breeding the male gets a breeding mask. a bold stripe of color will appear between and around the eyes like a raccoon.
the auratus and the chippokae are often mistaken for each other since they share simmilar female coloring. the auratus has a thin white stripe against the black stripe where the chippo is yellow and black only. the male auratus keeps the female coloring even when matured. mbuna are best kept with other mbuna as they are too aggressive for other malawis.
good luck with your new fish!
hth
maggie