Red Cap Oranda

Question
I have a Red Cap Oranda, who has been acting very odd. Its almost as if there is too much air in his belly and he can't seem to swim. He is constantly floating to the top of the aquarium and doesn't seem to have the strength to swim. I've had him for about 6 months now, and he continues to float to the top and lay upside down as if he is dead. (he is NOT dead) The other day I noticed his back lower fin is red, and seems as if it is bleeding internally. Does anyone know what could be the problem, or what I can do to fix this? I do 30% water changes about once a month, and make sure the filter is not clogged. I also have a black moor, an orange oranda, and a algae eater in the tank. These other three fish are all between 6 months and 4 years old. Help!

Answer
Hi Andrea,
I found this question in the "pool" of unanswered aquestion, sorry for the slow response.

Your Oranda is most likely suffering from a mixed infection. Swim Bladder disease is one of the problems. You've unfortunately left the problem a little bit too late, so you will have to take action fast, to save your sick fish. The red sores are likely a bacterial or viral infection of carp fish. Since I don't have a picture, it's impossible to tell, but I would go to the fish store and buy a broad-spectrum antibiotic. Here's a good link for diagnosing fish disease:
http://www.fishlore.com/Disease.htm

Once you have diagnose any diseases, go to the fish store to buy the appropriate medication. Then, take the following steps:

1) Immediately change 20% of the water, along with a gravel vacuuming.
2) Isolate the fish, (to prevent other fish from getting the disease)
  <If you have a separate aquarium, if not, leave it in the tank>.
3) Remove any carbon from the filter,
4) Use the medication, following the instructions CAREFULLY.
5) Optional : Add an extra airstone during treatment, to reduce stress.

What kind of algae eater is it? Most are tropical fish, which means that they should not be kept with goldfish, because they are warm water fish, which means they need a heater. Goldfish are cold-water fish, which means that they cannot be kept with a heater.

Performing one water change a month is insufficient, and large amounts of nitrate may accumulate during this period. In the future, I would recommend performing 10% water changes every week, for better water quality.

I hope your goldfish recovers!