FishProfiles.com Message Forums

One of my Oto's has a big white spot on his back, just in front of his fin. It is about 3/8 inch long, ovalish-shaped. I cannot tell for sure, but I do not think that it is raised. Behavior is not unusual, which is to say that he sits on a leaf for an hour and then moves to another leaf when the light is on. Planted 90 gallon tank. Temp=77F. No Ammonia or Nitrite. PH does fluctuate due to soft water but currently at 7.0. Weekly 40% water changes. Just started using Flourish for first time last week-end. Sorry not to have my digital camera right now. My biggest fear is that this is the dreaded white spot that turns manifests into an Ich outbreak but it isn't the initial white spot round and raised? Any thoughts?

The dreaded white spot would show as something much smaller, around 1mm or so, 3/8" is quite a substantial mark.

White or grey? Fluffy or just matte? Any red raised edge? Does it look ulcered?

It sounds like a skin infection to me, in the right position for a saddleback presentation of flex or similar, but I'm sure someone can be more specific.


With the pH, are you using shell grit or oyster shells etc? What does it settle at if you don't use chemical adjusters?


For animals, the entire universe has been neatly divided into things to (a) mate with, (b) eat, (c) run away from, and (d) rocks. - Terry Pratchett

From a bit of looking around, I would guess at columnaris perhaps? it seems to be the diagnosis closest to your symptoms. Perhaps some sort of other fungus or bacterial infection?

This Oto was on a leaf right out front just now so I got my best look at it. It is as though somebody painted a white patch on its back. It doesn't look raised. There are no other colors on the patch. It looks to be slightly greater than 1/4 inch long.

I do keep a mesh bag with some crushed coral in one of the filters but the water company has been adding soda ash to the water this winter to treat some copper levels that they detected in the water.

Thanks.