Koi Health Ailments

Anchor Worm is a tiny thread-like crustacean that buries itself under the scales of Koi and thus enters the dermis where it is parasitic. Heavy infestations can severely deplete a Koi strength and lay it open to secondary infection.

Anchor worms can be seen with the naked eye but a hand magnifier will spot them more readily. Treatment is with a proprietary solution such as Dipterex, Dylox or similar. The Dipterex will kill larval stages present in the pond.

Black Spot Tiny black spots appear over the body of the Koi. They are cysts of a fluke which lives in the intestines of birds. The Koi is a host carrier of the flukes so the cysts do not actually do much harm to the Koi.

The eggs of the fluke pass from the bird via its feces into the pond where they hatch to infest snails; from these they progress to the Koi where they bury into the outer skin before forming a black casing around themselves.

Try one of the modern remedies from your dealer or vet.

Carp Pox This condition shows itself in the form of gray transparent blister-like spots which increase in size and eventually merge. The cause is viral in origin and is usually the result of overcrowding and/or dirty water conditions or unclean pond filters.

There is no known cure but fortunately if the conditions thought to cause the problem are corrected then the condition cleans itself over a number of weeks.

Cloudy Eye Like carp pox, this Koi Health Ailments is an unspecific condition in which the eye appears to be covered by an opaque film. It is thought to be bacterial and due to incorrect water conditions, but may also be linked to other identifiable Koi diseases. The addition of pond salt to the water may prevent the condition.

Common Colds is another Koi Health Ailments, Koi can suffer from. Common colds will show itself by the Koi having a dull color; the eyes may appear cloudy.

Common colds are caused by fluctuating water temperatures or by a poor diet that stresses the fish. Stabilize water temperature and feed high protein diets until the Koi recovers thereafter maintain more stable conditions.

Costia affects both the skin and gills of Koi, and reproduces itself by binary fission. Infestations of this parasite can appear vary rapidly, and Koi suffering infestations exhibit the classic symptoms of lethargy, damped fins, rubbing and flashing and the skin can take on a grey white opaqueness.

A high magnification must be used to view these parasites (300x) and staining is recommended for postive identification.

Recommended treatments include Potassium Permanganate, Acriflavine and strong salt baths of 3 percent (4 and one half oz. per gallon).

To find out more about Costia click here. There is also a Picture of Costia on this page.

Cottonwool Disease This is sometimes known as mouth fungus. Although associated with the head, this Koi health ailments can affect any part of the body.

It appears like a grayish film that steadily spreads and can become ulcerated. It is highly contagious and can be transferred by equipment or contact with diseased Koi.

It will rot the mouth parts away so must be treated with urgency once spotted. Treatment is by any of the antibacterial compounds now available.

Addition of salt to the pond water will greatly reduce the possibility of the disease which is most likely under dirty water conditions or by introduction of diseased Koi which are not subjected to quarantine periods before being placed into the pond.

Cuts Minor cuts and abrasions can be treated by painting with mercurochrome or povidone-iodine for 3-5 days. An alternative is to place the Koi in an isolation tank containing a suitable solution that will keep the wound disinfected.

Dropsy is a Internal Bacterial Infection that has invaded one or more of the fish's organs. Fish suffering with this condition have scales which stand away from the body after the manner of pine cones as they open. The abdomen becomes swollen and the fish swim with difficulty and find it hard to breathe.

The cause of the disease is not understood and it may well be two or more conditions happening at the same time and of both bacterial and viral origin. In an advanced form, it is usually fatal. Watch for it in the springtime. Sulfa drugs may help or the addition of oxolinic acid to the food. If possible place the Koi in a tank at a slightly higher temperature than in the pond and give a salt bath or one of the antibacterial treatments. Given its unknown source, any affected Koi must be isolated immediately and the pond given a low level of general cleansing treating by the addition of salt or other treatment.

Finrot Fin rot can be the result of a bacterial infection, or as a fungal infection, which rots the fin more evenly and is more likely to produce a white edge. It could be mistaken for fin-nipping and it is essential that you treat promptly because if the rot spreads to the body the Koi will die.

Initially, the inter-fin ray membrane becomes opaque and then starts to rot thus exposing the fin rays which in turn rot. The process continues on fins or tail until it reaches the body. Fish which are badly handled or are kept in unclean conditions are likely to suffer this ailment. If one Koi is spotted with it, check every Koi in the pond.

In aquaria common treatments are to do a major water change, add aquarium salt if the species can tolerate it, and make sure that a healthy balanced diet with a lot of vitamins is provided. There are many commercial medications available for treatment.

A Koi Vet may cut away the infected fin or, if caught early enough treat with a modern antibacterial remedy; as always in these cases, it is quite pointless treating the fish without also identifying and correcting the likely factor: the pond water.

Fungus Disease If you see strands of cottonwool type filaments hanging from you Koi, it probably has fish fungus. These strands may have a green appearance due to algae growth on the fungus. The cause usually commences with the fungus feeding on the site of a small wound and then it spreads over more and more of the body.

Koi Health Ailments treatment is with malachite green, salt, or any of the proprietary fungal compounds now available. Once removed, the site of the wound should be treated with Mercurochrome by painting.

Gill Flukes Flukes are tiny, often microscopic, trematode worms and may live in all Koi and not be a problem. However, if the fish becomes ill or stressed, this is when such parasites can multiply and create fatal situations.

The flukes lay eggs which hatch onto free swimming larvae that infect other fish. Many are monogenetic which means they reproduce asexually and spend their whole life within a single host.

Flukes are one of the most common and dangerous parasites. They actually carry Aeromonas and Pseudomonas bacteria which are responsible for causing sometimes incurable ulcers in fish. And -- flukes are very fertile. Once you get rid of the adult flukes you must re-treat to get the babies that have hatched. Salt will not touch flukes.

Potassium permanganate is an excellent treatment for Flukes.

Gill maggots are the mature females of the parasitic crustacean Ergasilus. Ergasilus (gill maggots) will appear as grayish black and white parasites several millimeters long infesting the gills.

Heavy infestations can cause severe damage, eroding the gill filaments and allowing secondary infections to develop.

Leech There are many leeches in freshwater habitats (maybe over 250 species) and they range in size from small to large and can easily be seen with the naked eye. They suck large quantities of blood from their hosts so they need to be removed quickly. They may also be carriers of blood flagellates which are tiny creatures that produce ‘sleeping sickness’ in Koi which appear listless.

Further, the site of leech wounds will attract bacteria and fungi so one way or another, these are creatures you do not need at all.

Unfortunately, they are not uncommon in ponds so it is a case of always being on the lookout for them clinging to your Koi. Once seen, remove the Koi and give it a salt bath (at the end of this article I explain how to do that) and this will loosen the grip of the leech which can then be carefully removed with tweezers, if it has not already fallen off. Dress the wound by painting it with appropriate treatment.

Lice There are almost as many species of fish lice as there are leeches and they also suck the blood of fish. They have strong suckers to cling to scales with so if seen (they may reach nearly one half inch in length) they should be dabbed with a strong salt solution to make them loosen their grip, or place the Koi in a salt bath.

Saprolegnia Fungus One of the most common fungal infections of Koi. The fungal spores will grow anywhere on the koi, including the gills, initially germinating on dead tissue. Their threadlike hyphae release digestive can absorb it, as the fungus grows these juices start breaking down living tissue.

Fungus on the body appears as cotton wool like growths, it is hard to tell if a Koi has it in the gills, but if it hangs at the surface gulping for air it is likely.

Trichodina Quite an interesting subject to view under the power of a microscope, Trichodina looks like tiny parasols or flying saucers. Good news. Trichodina isn’t as bad as the rest and normally just makes the fish itch. Bad news. It does help introduce bad bacteria into the internals of the fish. Itching causes the fish to scratch (or flash) and the fish can lose scales or puncture its protective skin and mucus coat, allowing harmful bacteria to enter the body.

Trichodina thrives in the muck in the bottom of the pond. Thorough pond cleanings should eliminate the threat of this parasite. This parasite used to be able to be treated with salt but, like Costia, is now immune and has to be treated by other medications.

White Spot or Ich this is a well-know problem to tropical fish keepers, but it also affects cold water species. White spots are seen dotted about the body and fins-they are tiny ciliates which can swim around to find a host-if they do not, they die within 48 hours. They bury themselves into the dermis where they feed on the bodily cells. They then fall from the fish after about three weeks and reproduce in cysts on the pond bottom. They are most active in warm waters. Repeat treatments are necessary so each batch of cysts is killed as it bursts to release free swimming ciliates (which swim by means of many hair-like growths known as cilia).

Minn Finn is a Great Product if your Koi have Ich or other Protozoal Parasites. It was rated the 2009 Pond Trade Magazine Product of the Year.

Nothing is more natural and more beneficial to your fish than performing a salt treatment at the beginning of the season. Non-iodized, mineral-free salt without YPS anti-caking additive in the correct amount kills ich and chilodinella.

It helps the fish develop and maintain a strong slime coat naturally. A healthy slime coat is a must for a healthy fish. It protects the skin of the fish while containing substances the fish’s body uses to fight off infection.

There is no reason to use commercial products that claim to build up the slime coat. They also coat the gills, making it more difficult for the fish to breath. Use salt instead. Salt also will not harm the beneficial bacteria (or any bacteria for that matter) in your filter.

Salt is a wonderful thing to use whenever something is wrong in the pond. It is important to know how to use salt correctly to get the most benefit from it.

Non-iodized, mineral-free salt is the safest and least expensive treatment to kill Ich and Chilodinella. It will kill certain plants also so you will need to remove them to a holding tank before you begin and treat them separately with Cure-Ick.

Use 3 lbs. of salt per 100 gallons of water. It sounds like a lot of salt - and it is! Spread 1/3 the total dosage of salt in the pond on the first day, 1/3 on the second day and the rest on the third day. Leave the salt in the pond from 14 to 21 days to allow it do it’s thing. Then make a 50% water change, followed by another 50% water change a few days later to dilute the salt.

We do not suggest leaving the salt in for more than the 21 days.

Salt can be used in this strength along with most fluke medications. When treating with Cure-Ick or other medications designed for ich, lower the salt concentration to 1/3 the dose.

Tip: Note that the salt that should be used is non ionized, often refered to as Ice Cream Salt or Rock Salt.