Bent Fin

Question
Hello, so I woke up this morning to see that my Goldfish had a bent fin. Throughout the day, it continued to get worse. The fin is still there, it is just bent upward. I have no idea what to do, I really like my fish, and my mom will freak out if anything happens to them. I currently have two Goldfish in a 10 gallon tank. They have plenty of room to swim around. They are smaller than your thumb. What can I do to make sure he lives? He has such trouble swimming around. It is very sad and depressing. Why did this happen, and what can I do?

THANK YOU

Answer
Brandon,
It could be a sign of stress or bad water quality. The 10 gallon tank is too small for the 2 goldfish. One alone needs 20 gallons minimum and 10 gallons minimum for each additional fish. To house the 2 you will need a tank no smaller than 30 gallons. Even the common goldfish, aka the comet, can grow to be 12" long. Even though they are small now, it would be in their best interest to upgrade to a 30 gallon. In a tank that is too small, the fish's growth will be stunted. The skeleton of the fish will stop growing, but the insides won't. They will eventually dies a very painful death. If the tank is 10 gallons than the filter needs to be bigger. What I mean is, for 10 gallons the filter should be for a 20 gallon. Are you doing your weekly water changes? It is very important to remove 25% of the water and vacuum the gravel every week. If you have not done any water changes, do a 50% water change now and replace it with clean conditioned water. Then once a week, change out 25% of the water. Make sure you are testing your water weekly with a liquid water tester. You test for ammonia and nitrite levels. If either one of them reads higher that zero, you will do a water change everyday until both levels are back down to zero. Once you have done a water change, the fish should look better. Let me know how things are going in a day or two.