Ketias
Aquarium Advice Newbie
I have a 30 gallon tank with 4 goldfish and a weather loach (overstocked, but I do frequent water changes, have 2 filters rated for 55 gallons running and I'm planning on getting a larger tank in the future). I took a 5 week vacation and left my parents in charge of the tanks. They did around 4 25% water changes in that time, but I noticed that my red cap oranda has damaged fins, a clamped dorsal fin and I can see some red blood vessels that I don't see on another one of my goldfish that has a clear tail too. The oranda is swimming around actively and doesn't seem to be acting strange so far. Does anyone have any idea what it could be? Ammonia and nitrite are 0, but nitrate is very high. I suspect the high nitrates could be causing it, but I'm not completely certain since all the other goldfish and the loach are acting normal, even the one with a minor case of swim bladder disease. I'd appreciate any help in seeing what's wrong with one of my little buddies 
