krib colors

I have 2 Kribs and 2 tiger barbs in a 25l tank. One krib is small and a dull grey/greeny colour with a spot on its tail, the other is a dark black like colour. The darker one always hides and doesn't surface often. Another thing i've noticed is he wont let any fish near him or on the ground...

so I decided to come look at my fish.  My kribs are just explosive with color, tried to get a couple good shots, I think they're gonna be rocking around the coconut soon.  My rams are also looking rather frisky.  You almost can't tell in the picture but my female krib is so purple she's almost...