I need help with a sick goldfish. I have had my 3 common goldfish for 3 months and the tank has cycled completely. I went on vacation and used a feeder block in my 20G tank. The block annhilated my tank! Algae everywhere, water very dirty and now 1 of my fish is sick. His fins are all frayed and are starting to trail white strings. He is also developing red patches around the bases of the pectoral, anal fins, and gills. He had a red spot on his tail fin, but that seems to have disappeared. He is breathing rapidly and is very lethargic. I transfered him to a 1G tank and treated both tanks with Maracyn and aquarium salt. Should I do anything else? Thanks!