This threadlike parasite is about half an inch long, and attaches itself with a firm grip on the bodies of goldfish. It is more annoying than dangerous to fish.

Treat the whole aquarium or pool with potassium permanganate, 1/8 grain per gallon in the aquarium, 1/4 grain per gallon in the pool. It is necessary to repeat the treatment three times at ten-day intervals. Do not be discouraged if the treatment seems to have no immediate effect, for it is the eggs of the parasite you want to kill. The worm itself must be pulled or clipped from the goldfish for immediate relief. The head or anchor, if not removed from the fish by hand, will drop off in time.

Flukes are microscopic parasitic worms which attach themselves to the gills, causing the fish to breathe rapidly and to come to the surface frequently for gulps of air. It must be terribly painful, for goldfish so infested jerk and dart about spasmodically. If not treated, fish stop eating, waste away, and die of starvation and exhaustion.

If the fish are in an aquarium, treat all of them. Disinfect the aquarium and refill it with clean water. If they are in an outdoor pool, examine all the fish and dip out the affected ones for treatment.

Prepare a solution of 5 drops of formaldehyde (which you can buy at the drugstore) to 1 quart of water. Put the fish in the solution, and then every minute, add 1 drop of formaldehyde for every quart of water, until the solution is built up to ten drops to every quart. Leave the fish in the solution for a total of ten minutes. Repeat daily until a cure is effected. Three treatments usually suffice.

This white parasite is less than half as large as the head of a pin, but when several hundred attach themselves to a goldfish it seems to be covered by a grayish white mantle.
There are several treatments. For every gallon of water in the aquarium, add 4 drops of household Mercurochrome. (This solution will not harm aquatic plants.) Put the aquarium where it will warm up to 80 or 85 degrees. After a cure is achieved, usually in about a week, change the aquarium water. Before returning the fish to the aquarium, swab affected parts with Mercurochrome, full strength, or with kerosene.

A strong salt-water solution, 2 heaping teaspoons of salt to every gallon of water, is used by some fanciers. Raise the salt water to the same 80- to 85-degree temperature.

Others have cured goldfish of ichthyophthirius by swabbing affected parts with kerosene daily and keeping the fish in a warmed aquarium. Two or three treatments usually suffice.

Aquariums should be cleaned and disinfected after a cure, for eggs of the parasite may settle to the bottom, hatch, and begin the process all over again.

The potassium permanganate treatment is also effective, and this is the only practical treatment for outdoor pools in which ichthyophthirius has been discovered.