The fins on my koi fish's back are folded like he has no fins. Why is this?

Question

he doesn't have ich

Answer 1

No it isn't ih. This is not normal behavior for a Koi and you need to first do a visual on your fish. Look for ulcers and fin rot, excess mucus, loss of colour, tumours and malformations, weight loss, swollen eyes, swollen abdomen. Parasites such as White Spot, Costia, Trichodina, Chilodonella and Flukes

Possiable problems:

Costia (parasitic) May show signs of the following
rubbing of body against rocks and pond surfaces
skin cloudiness due to excess mucus
focal redness
long spells of lethargy at the pond bottom with clamped fins

Finrot/Tailrot (bacterial)
begins with light, foggy patches on the skin or fins
progresses to bloody, rotten tails or fins clamped fins

Skin Flukes (parasitic)
whitish or cloudy skin due to excess mucus production
rubbing of skin against rocks and pond surfaces
long periods of rest at the bottom of the pond with clamped fins

Does your koi show any other signs like not eating, swimming funny?

If your water quality is up to par, you are going to have determine what best suits the problem.

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Answer 2

They have "clamped fins." Try adding a small amount of salt to the water and then change back to fresh water. Ask your local aquarium or pet store for the right amounts for your size of tank. Also, check the water temp. Are they outdoors in a pond or inside in a tank? Although cold water fish, if they are relatively new, they may be used to a slightly higher water temp than what you have them at now. Good luck!

Answer 3

Do a 20 percent water change and check the quality of your water. Is your water sort of murky white because thats an indication of high ammonia.

Answer 4

Often that's an indication of stress. Check things like ammonia, nitrites and nitrates. If those are good keep a close eye on him for any other signs of disease. If he will eat, it's probably nothing serious.

MM