Please help me identify this lesion.

[rockman]

This came on over the course of a week. The skin is perfectly smooth to the touch over the lesion. There are no raised areas. Fish behavior is unchanged - he's still the greediest and gentlest fish in the pond. No other pond fish appear to have this. Water quality is good; same as last week.





Could this be disappearing beni or something infectious, bacterial or fungal?

Thank you very much for any thoughts.

[Russell Peters]

Quote: Originally Posted by rockman This came on over the course of a week. The skin is perfectly smooth to the touch over the lesion. There are no raised areas. Fish behavior is unchanged - he's still the greediest and gentlest fish in the pond. No other pond fish appear to have this. Water quality is good; same as last week. Attachment 16281 Attachment 16282 Could this be disappearing beni or something infectious, bacterial or fungal? Thank you very much for any thoughts.

Looks like a coldwater fungus, try pro-form C.

[kingkong]

Good luck..nice koi.

[Russell Peters]

Quote: Originally Posted by kingkong Good luck..nice koi.

What do you think it is...........it's not Hikui.

[rockman]

Quote: Originally Posted by Russell Peters Lokks like a coldwater fungus, try pro-form C.

Thank you very much for the advice. My salt is 0.2%. Do you think I need to decrease it before using pro-form C? I saw online that pro-form C should be used only in a low-salt environment.

[rockman]

Quote: Originally Posted by kingkong Good luck..nice koi.

Thanks!

He actually has a sweet personality, too. He swam serenely into the net and sat there quietly, as if he wanted to be petted.

[kingkong]

That is what I was thinking (the H word)...beginning stages but I didn't want to say. Sunburn maybe?

[Richard Rombold]

Could be several things, but Russ is correct that proform-c is a good start. Do a large partial water change to reduce salt levels and take the fish off feed. Then follow the label directions. Three treatments all together. It's probably a simple protozoan infection on the skin. The fact that your koi was so docile though leads me to believe that it's gills are also severely affected. Treat it with care and do the first treatment when you can watch over it. If it shows signs of stress then net the fish and place it in a quarantine tank with .6% salt levels and good aeration. It may not be strong enough to survive the initial treatment.

[rockman]

Quote: Originally Posted by kingkong That is what I was thinking (the H word)...beginning stages but I didn't want to say. Sunburn maybe?

...not in Seattle.

[Russell Peters]

Quote: Originally Posted by rockman Thank you very much for the advice. My salt is 0.2%. Do you think I need to decrease it before using pro-form C? I saw online that pro-form C should be used only in a low-salt environment.

Salt and pro-form C do not mix. I would do water changes to get rid of the salt.