Personally I think its harsh to have even 1 in such a small territory...
1 might be ok in 200L but will outgrow it eventually, some faster than others... small RTS (or whichever colour variation you go for) are lovely as babies but as they grow, they get meaner and meaner...
2 will likely fight constantly unless you are lucky. In my experience... about 1 in 20 can keep multiple RTBS (or whatever colour you go for) together.
Not like they are a lovely active, easily visible species to keep... plenty of better choices out there!! How about Flag Tail Porthole Catfish?