A Black Spot

I have two Koi and two goldfish in a 600 gallons pond with a 1200 pump mag-Drive and a Jebao PF-3 Bio Filter with 11 Watts UV. This morning one of my goldfish had a small black spot on the side of the belly. I have been doing water tests weekly and I don’t see anything wrong with the water. I don’t know what could be wrong. Any Ideas? -Patrick Patrick, The black spot on your goldfish is probably a small cosmetic flaw, caused by a bad gene. Koi people usually call it Shimi. It has nothing to do with water quality and it does not affect their health. There is a small possibility that it could be a parasite, like a fish louse or an anchor worm. But it's unlikely and you'd notice that your goldfish would probably be acting funny. Share: Del.icio.us Digg Reddit