Hi, I'm totally new to keeping tropical fish and hoping for some advice, i was given a rainbow shark out of a cold water tank so went and bought a 126 lt tank, all levels, pH an temp, are good and have a few live plans in there, had it running for five weeks now, my son picked are first fish which he happened to pick tiger barbs and unfortunately the rainbow shark tried to get rid of them and attacked them none stop for thre days and nights, so decided the rainbow shark had to go not realising that the tiger barbs where quite aggressive aswell so now I have 6 tiger barbs in a tank and we would like somthing colourfull and bigger any suggestions please