Blue and yellow ones eh?
Well youve got a tonne of choices, Be carefull about picking your fish especially if they are mbuna, NEVER buy from a mixed african tank, and try to check out around here before purchaseing anything, read pinned topic about mbuna these tend to be the commonly found blue and yellows in the store for a start
For a setup, Africans like rocks lot's of rocks and caves so put as much in there as you can, Sand is preferable, IMO harder to keep clean but they cichlids really like it better they are much funner with it. Plants are very limited if you are setting up a mbuna tank these are hebivores and will eat them, other cichlids are not great with plants either real or fake you will have a hard time keeping them in place. Cichlids are fun to watch grow but do so quite quickly fish like the zebra, caeruleus in your avatar, and most mbuna will fit in the 55 gallon at full size, so look around the internet check out the fish index here see what fish you like and come back with some stocking questions