You might be pushing the envelope . I had in a 6x2x2 two big malu nems one up either end of the tank. I had a pair of adult Maroons,some time later I added 5 young percs.
The Maroons would let them nowhere near the spare nem,they became relegated to hideing out in the forest of pulseing xenia .
Clowns are at the end if the day Damsels ,and you know what they are like