I found that when I had 2 Dwarf Gourami (one male one female), the male constantly harassed the female. Then it became better once I put 6 pearl gourami in the tank. He decided to chase the bigger fish around :lol:
I might suggest getting more to spread the aggression out amongst a larger group?
I'm not sure about the other fish in the tank sorry.
Though 6 is a good number for clown loaches, but the more the merrier. You will see them more often