If you're putting the clowns in with aggro cichlids there are a couple of things:
a) more space, big tank. CL are very active and grow big, though often relatively slowly. Having said that, their slow-growth reputation is in no small part based on people keeping them in smaller tanks (IE:<100G) with insufficient filtration & water quality & that wild-caught often need gut parasite treatments.
b) habitat- bamboo or PVC segments, driftwood etc., even oak-leaves, so they can hide and break up any territorial issues among themselves as well as with the cichlids.
c) flow- get a powerhead or Koralia to set a good flow along the bottom in at least one part of the system. And crank up the temperature- clowns come from & do best in water that's well toastier than the home-rivers of red terrors.
These are also lazyman's short-cuts to the most important part- perfect water, and are particularly important as tiny juvs are really sensitive.
That looks like a great school. You will find these quickly become your favourites in the tank... for the next 50-odd years. I find it a shame that these fish can sometimes be sooooo cheap in the US as it cheapens them and people stop investing in their care. They cost us >20$ per around here, so a school gets ridiculous-spendy and you invest all-in.
A