what are the actual measurements of the tank as shoaling fish need quite a lot fo surface area to move around in
I had WCM in a 30l 18x10x10" and they seemed happy i only had 6 in there
if you are going for WCM why dont you try the golden WCM or the longfin instead of the standard ones
even though all are lovely
I myself quickly converted that tank to a shrimp tank with amanos and cherrys in and they are great fun to watch , the cherrys will breed like rabbits in the right conditions
the only thing i would say is make sure all your tak is fully cycled with 0 readings in ammonia and nitrite as this will kill shrimps very quickly