From 1/8 to 1/4 grain per gallon is a good solution strength for treatment of fish in smaller receptacles. Leave them in the solution for two days, or until they show signs of exhaustion.

   You can drop the potassium permanganate directly into pond or aquarium, if you like, for it will act as a tonic to aquatic plants and other goldfish there. Be sure to remove snails, for the solution may kill them. Also remember that potassium permanganate will kill off most of the algae.

   Some ailments require repeated treatments with potassium permanganate, but such treatments should not be given more often than every ten days. The water need not be changed between treatments, for the chemical expends its energy in two to three days, and the strength is not cumulative.

   Ask the druggist for the "fines" potassium permanganate, for it dissolves much more quickly than the crystals. Keep the chemical dry until ready for use; it weakens in solution.

   The effects of an ammonia solution-10 drops of household ammonia to 1 gallon of water-are sometimes beneficial. Leave the ailing fish in the solution 5 minutes, or until there are signs of distress. I have not personally experimented with this solution. Until I do, I would not advise it except as a last resort to rid fish of some extremely stubborn parasite.

   It is a wonder that the short, squat bodies developed in various breeds have not crowded the internal organs into unnatural arrangements that produce more stomach trouble than they do. As it is, almost the only disorders due entirely to cramped body formations are constipation and swimming bladder trouble.

   The excrement of a healthy fish is brown, usually in long sections, and without bubbles or slime. Any departure from this norm, particularly if coupled with sluggish behavior, indicates constipation. There are several easy cures. You can sprinkle a pinch of Epsom salts into the water every week as prevention, or give scrambled eggs (sprinkled with Epsom salts), chopped lettuce leaves, spinach, or chopped earthworms (smeared with castor oil) as laxative foods.

   For more drastic cases, transfer the fish for two days to a solution consisting of 1/2 ounce of salt and 1/2 ounce of Epsom salts to 1 gallon of water.

   Since overfeeding is a common cause of constipation, reduce the diet a bit after recovery.

   This ailment, which seems to be confined mostly to tropical and fancier breeds, is one of the worst, but comparatively rare. The affected fish seem well except that the body swells and the scales stand out at an angle, like the seeds of a pine cone. Fish may live several days with dropsy, but there is no known cure for it.