Red earred slider

Question
We have two 10yr old and one 15 year old turtles.
The female 10yr old got out the cat door in Oct and was missing for several weeks. They all live in a large horse trough in the house, with adequate ligting.
The females shell has started getting light spots on top and they have pretty much spread. The underneath is starting to look like it has loose surface shell spots. They get great light and shade.
We have been scrubbing the shells with a providine/water mixture twice a day for the last week and letting it soak for 10 min.
The water is filtered and those are changed every day.
The other turtles are not showing any signs.
I hope this is not shell rot.
A vet said it was not and suggested the current treatment.
I do not think that he deals in many turtle of this kind in Montana.
Please send us ideas
Thank You
Wilma

Answer
Hello Wilma, thank you for taking the time to research further. Your vet in on the right track.  You didnt mention the temps of the enclosure. This will need to be addressed.

What youre describing sounds like a fungal infection. The iodine and water mix are good you can also add salt to the water more often.

Also, you really should seperate the turtles until the infection is resolved as fungus can be spread between them and it will never go away with them sharing.
Do not pull up on the shell that is lifting, allow it to fall off on its own.  

Did he tell you to allow him to dry out a few hours a day take out of the water.
Allow it to sit in an enclosure while drying out then leave out for a while, introduce back to the water Repeat htis several times a day. This willa ssist with getting the old shell off. It can easily turn into shell rot and will still need vet follow up if it doesnt resolve with the treatments.
Be sure to keep water clean and temps up. Let me know if I can be of further help