I desperately need some help. I, stupidly, agreed to take my boyfriend's brother's fish and tank without seeing them. My boyfriend knows nothing about fish and fishkeeping so all he said was that it was a big tank and there were 3 large fish it in, one being a common pleco. Well, they brought the tank and fish today. The fish were in 5 gallon buckets. I looked and was shocked by what I saw. Not 3 fish but 5 very large fish. My boyfriend was right. One is a common pleco. The other four are comet goldfish, I think. I know nothing about goldfish. I have a tropical aquarium. I've been looking at pictures of goldfish and koi and I'm pretty sure they are comets. One is 12 inches long, one is 10 inches long and the other two are about 7 inches long. I didn't even know how big the tank was so I measured it and checked out a volume calculator online and it works out to be a 25 gallon tank. 25 gallons! And to make matters worse, these fish lived in horrible conditions. The water that was in the buckets with them was so dirty you could barely see through it. One of the 7 inch fish is missing an eye. I don't know if it was born like that or not. I do have to say that the fish look healthy. Even the one-eyed one. I have no idea of what to do. I know nothing about goldfish but I do know that the tank is way overstocked. They can't swim without bumping into each other. What should I do? What should I feed them? How much should I feed them? Any help would be appreciated.