Prevention Methods for Koi Fish Skin Rot and Death and Recommended Tank Mates

The most “popular” fish lately is undoubtedly the koi fish. As the perfect “spokesfish” for good luck, it has prompted people to rush out and buy koi to keep at home in the hope that good fortune will keep coming their way. But raising koi well still takes some careful thought, so how do you raise koi fish so they won't get skin rot and die? And what fish can they be kept with?

1. What should you do if a koi fish develops skin rot?

In most cases, skin rot and flesh rot in koi fish means they have come down with “red skin disease,” which typically shows up as congestion of the surface skin, loss of scales and rotting.

The main causes of red skin disease are: water pollution, low content levels, high organic matter content, parasite infection and so on.

How to deal with koi skin rot:

1. Replace nearly 1/4 of the water in the fish tank or pond, and give the fish tank or pond a cleaning and disinfection.

2. Isolate the koi fish with skin rot, and feed it with a detox and liver-protection product plus a vitamin anti-stress product mixed into its food, 2 times a day, once in the morning and once in the evening, for 7 days in a row, to see whether there is improvement; if there is no improvement, continue feeding.

3. Strengthen feeding management and keep the water clean and fresh. Regularly sprinkle nitrofurazone or furazolidone over the whole pond or fish tank.

Generally speaking, skin rot in koi fish is a chronic disease that is relatively hard to treat, so prevention should still come first.

2. How do you raise koi fish so they won't die?

1. Maintaining water quality

Koi fish produce a lot of waste every day. If you are keeping them in a fish tank, it is recommended to add a filter to the tank and change the water once a week (replacing just 1/3 of the tank's water volume). If you are keeping them in a pond, you should also clean and disinfect the pond regularly.

2. Pay attention to water temperature

Koi fish actually have a fairly wide tolerance range for water temperature; basically they can survive well at 5-30°C, so you just need to take good cooling measures in summer and warming measures in winter.

3. Feeding

Animal feed, plant feed or synthetic artificial feed can all be used to feed koi fish. Specifically:

(1) Animal feed: bloodworms, water fleas, cyclops, paramecia, tubifex worms and so on.

(2) Plant feed: generally plant feed should be fed less; common aquatic plants are all fine.

(3) Artificial feed: synthetic artificial feed is also quite suitable for koi fish to eat, and its nutrition is fairly complete.

As for feeding frequency, juvenile fish can be fed 3-4 times a day, while adult fish need only 1-2 times.

3. What fish can koi fish be kept with?

Koi fish are fairly gentle-tempered freshwater fish, so if you want to keep them with other fish, you must also choose gentle-tempered species, otherwise the koi fish will easily be attacked and end up injured or even dead.

Recommended species: plecostomus, goldfish, grass goldfish, koi crucian carp and so on.

Among these, the plecostomus is a tropical omnivore, so beginners are advised not to try keeping it together with koi fish.

Notes on mixed keeping: the number of other fish kept together with koi fish should be kept at a moderate ratio, as only then can both sides, and all parties, get along harmoniously.