What size tank is the shark in and with what other fish? Don't put them in the 10 gallon as that's already over-stocked and overcrowded. Tiger barbs are active and nippy and will not do in a small tank. Also, cherries are not a schooling fish. Get a pair or trio if you want some but put them in a larger tank with relatively peaceful fish. BTW, I should warn you that there's no guarantee a fully grown, 6", RTBS won't try to eat them (probably won't actualy catch them, may not actualy manage to swallow them but may possibly try - and cause injury and stress in the process).