lumps on fish

[Don4921]

In another pond i have (about 3,000 gallons) My full grown doitsu koi has started to grow a small lump on its side and it does not break through the scales help

 

[DeLgAdO]

ive had that on one of my koi before

could be a tumor

 

[guppy]

Since there is no parasite showing through the scales it is not a macroparasite. If the lump is small, well defined, and waxy looking it would be carp pox, expect more lumps in that case, there is no cure but it is not lethal. If the lump is ill defined and firm it is probably an encysted sporozoal infection, unless it invovle vital organs it is also very rarely lethal though they do sometimes rupture and the wound that is left is vulnerable to bacteria or fungus. I cannot find a cure for it. 1 1/4 oz salt per 10g water is supposed to prevent it from spreading to other fish if it does rupture I would advise getting in touch with a local koi breeder for hands on advice.