• Anchor worm – A parasite that attaches its anchor shaped head to the body of the fish, usually near the fins or tail. It looks like a little white stick protruding from the fish. After attaching to the fish it irritates the area and redness appears. You can remove them by gently pulling them with a pair of tweezers as close to the scales as possible. Once removed swab the lesion with 7% tincture of iodine to prevent infection. Anchor worms are introduced into the pond by birds.

  • Costia – A parasite that attacks fish when their immune system is shut down in the late fall and early spring. Symptoms include red fins and labored breathing. Spider web lesions and excess mucus are also common. Treat pond to a 0.3% salt level using non-iodized salt. To prevent it from occurring salt pond to 0.3% in the fall and again in the spring before the fishes immune system kicks in.

  • Dropsy – Also known as pine cone disease is manifested by the scales on the fish protruding much like a pine cone. It is caused by a buildup of fluids within the fish. It is a bacterial infection that is not infectious and is thought to be caused by food rotting in the intestines from slowed metabolism that attracts the bacteria. It is frequently fatal and must be treated with antibiotics.

  • Epistylis – Cottony tufts appear around the mouth, fins or tail of the fish. When it gets up to the gills the fish suffocates and dies. Epistylis is treatable by salting the pond to 0.3% and maintaining it for 1 week. It is easily confused withSaprolegnia fungal attacks which manifest themselves when a fish is terminally ill.

  • Flukes – There are two types of flukes, Gill flukes and scale flukes. Both manifest with the fish getting close to an object and quickly flipping their tails trying to scrape the parasite off. Treatment requires the use of potassium permagate. If you can isolate the fish in a tank you can treat it with fluketabs.

  • Fungus – Saproleginia fungus is often confused with Epistylus as the symptoms are similar – cottony tufts found around mouth, fins and tail. The fish will also dart around and open and close its mouth in erratic fashion. This disease usually occurs after a bacterial infection while the fishes immune system is low because it is near death. The colder waters found in the late fall and early spring increase occurrences of this disease. Daily treatment with malacite green until fungus is gone is necessary (Be careful as overdoses will kill fish). Treat with 0.3% salt solution first as Epistylis is more likely unless you have treated for a bacterial infection.

  • Ich - Also known as white spot disease is caused by a parasite that floats in the water until it attaches itself on the fishes body. When the spots spread to the head and gills the fish has difficultly breathing and dies. Treat with non-iodized salt in a hospital tank and raise the water temperature gradually over a 2 day period to 85° F for 2-3 weeks. Before returning the fish to the pond treat the pond water to 0.3% salt for 2 weeks to kill the free floating parasites or you will be doing this again real soon.

  • Septicemia - A condition in which bacteria has entered the internal organs of the fish through a wound or ingestion. Symptoms include clamped fins, bulging eyes, red bellies or reddened and eroding fins. Treatment includes 0.3% salting and antibiotics that are injected or ingested for 2 weeks. You can reduce this risk by making sure there is no crud in the bottom of the pond in the fall because it is the bacteria that is found in the decomposing material that causes the illness.

  • Ulcers - Caused in the spring when the fish are spawning and injure themselves or scratch themselves. Bacteria enter through the wound and because the fish have a very low immune system at this point they cannot fight off the infection and it grows into an ulcer which left untreated will kill the fish. Treatment requires removing the fish and putting it in a hospital tank where you can monitor its condition. You will swab the wound area with hydrogen peroxide and then 7% tincture of iodine to cauterize the wound and begin feeding the fish antibiotic medicated food. You can reduce the risk of this occurring by keeping a clean pond and filters during the winter.

A word of caution when using salt - There are many different opinions about treating ponds with salt. Whether you do or not is more about your comfort using it to help heal your fish. It is effective in treating some ailments and should be part of the treatment options for a sick fish. It does come with caveats:

  • ​Salt does not evaporate out of your pond and if you salt to heal a fish each year you will be doubling the percentage of salt in your pond and that can kill fish and plants. 

  • The only way to get salt out of your pond is to pump the water out into your yard and replace it with fresh, unsalted water.

  • It is not a tonic to your fish. It is an irritant, forcing your fish to produce a thicker slime coat to protect it from the salt. The thicker slime coat suffocates the infecting organism.

  • Many plants are not very tolerant of salt and will turn yellow or die, like Water Hiacynth and Water Lettuce. Victoria lilies are extremely sensitive to salt.

  • Keeping your pond salted year around is like taking antibiotics year-round, not the best idea. The longer it is in the water the more resistant the bugs can become to it.

  • It is a very good idea to buy an electronic salt meter if you are going to include salt as a treatment option. They are under $50.

  • ​Only use basic rock salt to treat the pond. No caking agents or iodine, just plain old rock salt.