catfish with swollen belly

Question
QUESTION: Hi David! I'm going to give you all the info I know to give you. I have a 20 gallon tank and it accommodates 5 fish. My 5 fish combined are about 21 inches. I do 10 to 15 percent water changes once a week and 50 percent once a month.My fish eat goldfish flakes and/or crisps three times a day and bloodworms as a treat twice a week. Yesterday all was well, and today my catfish has a very swollen belly. There has been no additions to the tank and I've had it up and running for about 2 months. I've also called petsmart and was told to bring in a small amount of the water to be tested. I'm going to do this shortly, but in all honesty David, I condition my water accordingly and suspect that the problem could go deeper than that. Please help me figure this out. Thank! I look forward to hearing from you.

ANSWER: Hello Walesca:  This is the information I will need:  the results of the water chemistry tests you had done today. If the catfish eating?  when you say swollen what exactly do you mean??? is his stomach extremely large, Medium sized, or ????  Is he pooping??? if so what color and what does it look like.  The bottom line is that there are several things that could cause a catfish to have a swollen belly... those could range from the fish carrying roe to dropsy, etc.  What kind of fish do you have in the tank???? let me know

dave

---------- FOLLOW-UP ----------

QUESTION: Hello David, Petsmart did not tell me much, for except that the water was fine and that it could be constipation. Anyway, I still would like your input on this subject.The catfish returned to normal as of yesterday. And as far as the other fish I have,which includes 2 orange goldfish,2 koi's, and the catfish, they are all doing well. Any suggestions on maintaining the health of my fish would be greatly appreciated, Thanks!

Answer
In addition to their normal diet include brine shrimp ( the shells help prevent constipation), frozen (thawed) green peas also will help prevent constipation, tubiflex worms and for the goldfish there is a plant you can buy that is called anachoris which they love to eat.  A varied and well balanced diet is very important to fish. It helps them stay healthy and is one of the best ways to help prevent disease.  regular tank maintenance is also important, clean the gravel and from time to time take the plants and decorations out and clean them too.  dave