Yeah i dont know if this has anything to do with the clowns but i see that you have:
Scooter Blenny, Tomini Tang, Mandarin Goby, Purple Firefish, Pistol Shrimp, Diamond Goby, Copperband Butterfly, School of Coral Catfish, 2 True Percs, Vermiculated Angel, Flounder
All in that 55 Gallon tank. Or am i reading that wrong? If your trying to keep all these fish in that 55 gal the problem good simply be overcrowding.