External wound on anus

Question

  I have a wonderful fish that I bought from Wal*Mart 1 year and 8 months ago. Unfortunately, I have researched, but I'm not sure the kind of fish. He is long, skinny and is mainly white with a few gold spots; he is a very long dorsal fin and long caudal fin. Three days ago his but became very swollen (it is worse now than when the picture was taken 3 days ago). I've also noticed there is some internal bleeding near the area and this morning it began to puss. Today I started to use Melafix, but I don't know if it will be beneficial. I really do not think he hit it on anything and he lives alone. What is most likely wrong with him and what can I do to make it better? Thank you so much!

Answer
Christy,    What is going on in your tank is the ammonia is so high it is burning him. Do alot of water changes. It is killing itself in its own wastes. Goldfish, contrary to popular belief are not made for fish bowls. Goldfish need BIG water. Especially the type you have they are usually used in ponds or as feeder fish for larger fish. This fish in the correct conditions can reach a foot to a foot and a half long. Also, can live for many years. This is the biggest problem with Goldies they need large tanks and great filtration. They are beautiful and full of personality but, they are the dirtiest little buggers. I would go and at least start with a ten gallon system. You can usually get them in a kit pretty cheap. You can save and let the tank grow with him always try to stay one size bigger than your tank needs for your filtration. For example if the filter is made for a twenty gallon get a filter for a thirty gallon. Its all about water quality and with these guys they are not tropical small fish so you will have to clean a little more often. Do a little research on goldfish. You will be amazed. I have a blackmor, black with the big bulgey eyes named molly. She lives with four cory catfish that are all about two inches. I have four two speckled and two green. They are so cute with their little fu man chu mustaches and they have no problem acclimating to the cooler waters. Instead of the pleco's (the brown algae eaters) you will see in some goldfish tanks that outgrow your tanks quick and just leave strings of poo everywhere. So the catfish are a much better clean up crew. They live in a 45 gallon tank with a canister filter called a magnum. It was abit costly I saved for it but boy it helps keep the tank more manageable. She is nine years old now. She is bigger than a baseball but, a little smaller than a softball and quite a character. Your fish by the time it is in a tank that size will need to be taken to a pond because it is going to just keep growing or you are going to keep going bigger tanks. Research types of goldfish. Make sure to check out about water quality,tank size recommendations,filtration, and fish growth. I will send you a site to start you out. Melafix is fine it won't work because that is not your problem. If you got him or her at a store with that tank shame on them. You can even copy this and take it to the store. Tell them I will give them a much more detailed explanation about why this was wrong. I would take it back to the tank you got it from so maybe it will make it and get the correct type of fish for that tank.

      Now that all being said no worries. Your tank has a nice bubbler and is perfect for either two female betta's (yes they will live fine together, the females) and they are very pretty colors. Now if you go with a male with the beautiful long fins just one and you could put a cory catfish in the bottom with him if you add them together they should be fine. They put out much less wastes live a few years and also have their own personalities. You will have to change the water abit less causing the fish less stress and it is so easy. I would once every couple weeks get a pitcher and dump some water from the tank in there and net them out and out them in the pitcher. Wash all you rocks and get a sponge that you use only for your tank and a bottle brush for your bubbler tube in warm water and your sponge,rinse well. Then just feel they are in and fill it close to the same temperature to the feel (dechlorinate as it fills if necessary) and net them back in. I usually give mine about ten minutes then I feed very light just to settle them. Just 20 minutes and done. If you have anymore questions please ask. I will send you a site on your betta fish and cory's too !!!! You will need a PH test kit. You will want to keep it at 7.0. If it is high you will need PH down from the pet shop. If it is low you can use abit of baking soda and water mixed. Add little drips with a small stir till correct PH. I feed mine a pea once a week. I just thaw under water a frozen pea and crack it . Then remove the shell later. This gives him the small amount of veggie they may nibble in the wild and it stops the chances of them contracting swim bladder infections and constipation. I feed mine frozen blood worms twice a day I think he eats about three and I drop a shrimp pellet every couple days to the cory he eats a blood worm here and there. ALWAYS make sure you new water is dechlorinated if you have city water. If it is from a yard well you are fine.  Good Luck Christy,  Tina

http://goldfish2care4.com/keeping-goldfish.html
http://www.better-bettas.com/a/betta-care.shtml
http://www.fishlore.com/Profiles-Corydoras.htm