my angle fish

Question
I have an angle fish in my aquarium that i have had for a few months. Just the other day though I noticed that she is VERY bloated and swimming on her side> It has been 3 days and she is still trying to eat and alive, but what the heck is wrong? I was hoping someone could help me with this one. I checked the water pH and everything is great! there are no other fish that are having any problems.  

Answer
Good evening Jessica,

What you describe sounds like a water quality issue and/or a swim bladder disorder. You mentioned testing the water, but did you test for ammonia, nitrite and nitrate? These first two - ammonia and nitrite - are toxic to fishes at any level and therefore must always be at 0 ppm. A healthy, cycled tank never shows detectable levels of either. Nitrates should be kept below 20 ppm at all times.

Angelfish grow large and one angelfish needs a tank of at least 29 gallons, a single mated pair would be fine for a 55 gallon tank. You may be able to get away with a single angelfish in a 20 gallon tank as a juvenile, but not for long. They are also a bit delicate, sensitive to poor water quality and susceptible to bloat, like many other cichlids. Diet plays an important role in keeping them healthy. A commercial food diet - flakes only or frozen food only - is not healthy. Here's a list of foods for tropical fish:
http://fish.mongabay.com/food.htm

It may give you some suggestions or ideas on what to offer. Fresh, frozen and dried foods make a healthy, varied diet. Flakes should be less than 50% of what is offered. Look for New Life Spectrum pellets - both nutritious and palatable.

After ensuring that the water quality is up to snuff - no ammonia or nitrites, nitrates <20 ppm - I would do a water change and gravel vacuuming anyhow. 25-30% would not be too much. For now, try offering shelled peas - frozen or canned is fine as long as it's thawed and unsalted - and add a bit of Epsom salt, 1 teaspoon per 5 gallons. Both will help to pass any blockages if constipation is the problem. Frozen brine shrimp and daphnia also have laxative properties.

If you do not see immediate improvement after the change in diet and water change, and you have confirmed that water quality is not the problem (remember that pH is only one part of the equation and an "ideal" pH isn't nearly as vital as having 0 ppm of ammonia and nitrite - by the way, angels like a low-end pH, but are adapatable, just make sure your pH isn't very high, 8.0 or higher) then administer medicated food containing Metronidazole. This is the active ingredient in Jungle's Anti-Parasite food, a pellet food, and also the active ingredient in this fine medicated flake food:
http://flguppiesplus.safeshopper.com/256/cat256.htm?901

If you cannot get medicated food, then treat in a hospital tank using a medication that contains Metronidazole. You may add Nitrofuranace (also called a Furan compound) and use these two medicines in tandem for the recommended duration on the package. I would only medicate as a last resort. A change in diet, high water quality, Epsom salts and peas and medicated food should all be explored first. Many diseases sort themselves out if the environmental conditions are fixed or made as ideal as possible. You can read more here about angelfish (and also Q&A answers about disease):
http://www.wetwebmedia.com/FWSubWebIndex/fwangelfishes.htm

I hope that helps, take care.
Nicole