Clowns, starting to develop black blotches?

[longhorn_20m]

My Occ. clowns are starting to develop black blotches on the mouth area and sides of head going down the side of the fish. The biggest area is around the mouth. I was wondering what this could be caused by?

Everything else looks good. The frogspawn, zoos, and green stars are growing like crazy and look better than ever.

I feed a mixture of pellets and frozen brine shrimp and also use chromaplex everyonce ina while for the corals?

Oh the tank is a 12 gallon JBJ nano cube, I'm not sure what the problem is, any ideas?

[mathias]

maybe its getting to small only being 12 gal?

[longhorn_20m]

u think?

[Instar]

Black blotches can be caused by a parasitic worm. Its easiest to see on the rim of mouth and the leading edge of fins. The 12 gallon nano is good for a pair of Oce's; that's not causing back blotches. If its outside normal color patterns for Percs and they are truly Oce's, I would be concerned. Make sure the water is right. Greenstar growth is not an indicator of water quality. If the tank has been set up for a while, it can approach toxic levels of some elements unless there are water changes. If you have softies, they can mess the water up with their own chemical toxins trying to compete for their space. Everything has its chemical defenses. If water is pristine, I would really start asking about a problem. Colors may darken or fade, but blotches only show up in response to something. Oce's don't blotch on light changes either like some fish do.

[longhorn_20m]

Awesome thanks. Well they are Occ. for sure. I'm not sure what is causing it, but I do perform a 3 gallon waterchange every two weeks. I do have zoos and frogspawn so it might have something to do with the toxins. I will look more closely at it today, maybe snap a few pictures.

Thanks
Justin