high quality red zebras are great in a mbuna tank, and for me a must, bright reddish orange coloration is a great stand out in the tank and compliments blue mbuna as acei , mainganos and msobos. Electric yellows are nice for the splash of yellow , although several species have yellow females such as the saulosi and msobo. Kenyis are another great colored one, they are a little more aggressive but if you crowd the tank things are fine, the females are light blue with dark blue stripes and the males are yellow....so a group of 12 females and a couples males is quite nice.