angel fish has eye infection

Question
My angel fish has an eye infection-white, large sack over one eye. sometimes it gets bigger and then smaller but won't go away. I've had my tank and the fish for about a year. I haven't added any new fish and the others are fine. It also looks like a smaller white area on one fin.  

Answer
Good evening Jordan, thank you for your question.

Your angelfish probably needs to be treated in a hospital tank with a broad sprectrum antibiotic. Angelfish are sensitive to water quality and need plenty of room, a 29 gallon tank for a single pair is really the minimum for this species. Before you medicate, consider the following...

Examine your water quality. There should be 0 ppm of ammonia and nitrite at all times in a healthy, cycled tank. Nitrates should be under 20 ppm, angelfish are more sensitive to nitrates than other hardier community fish.

Are you perhaps overfeeding? Not changing enough water? A minimum of 30% a week is my recommendation for all but the lightest stocking levels, 15% twice a week is best. Filters should be rinsed in tank water or replaced (if they are disposable) weekly, and gravel vacuumed every two weeks.

The start of fin rot and a more advanced case of popeye seem to be what's bothering your angelfish, and these are usually due to poor water quality (although an eye injury is plausible) which you can remedy. Make sure your water quality is optimum, and your gravel clean, and watch for improvement based on these factors alone. If not, then...

Separate your angelfish to a hospital tank. Use Maracyn or Erythromycin according to the package directions. Keep in mind that you will need to change the water twice daily to keep the ammonia and nitrites from building up - it's nearly impossible to keep a hospital tank cycled and healthy when it is being medicated. Use dechlorinated tap water that's been left to sit a few hours in advance, if you can.

Prime works best for me in hospital tanks and is my dechlorinator of choice, mostly for its ease of dosing, just add 3 drops per gallon. If you cannot find these meds, look for a broad spectrum antibiotic in your local fish store and follow the directions exactly. Keep in mind that some medications are photosensitive, the package will usually say if you have to dose with the lights off. I would research whatever type of medication you use by typing it into Google - I always like to know as much as possible about what chemicals I put into my tank. I try to keep them at an absolute minimum. Make sure you are stocked on test kits, you will need to monitor quality at least once a day.

A teaspoon of Epsom or aquarium salt per 10 gallons of water will help with stress during treatment. Dissolve the salts in warm dechlorinated water first, then add the salty water to the tank. Keep in mind it does not evaporate, so only add another teaspoon when 10 gallons have been changed out. Some folks add Melafix, IMO it neither helps nor hurts.

Good luck with your angelfish. Do have a look at this site and the linked files above for more information:
http://www.wetwebmedia.com/FWSubWebIndex/fwangelsysfaqs.htm

Take care,
Nicole