I have a large 5 year old RES, lives outside in a small contained pond in Florida. He appears perfectly healthy but his shell has a small white spot, that is getting larger. The spot is hard and does not ooze or smell. We've brushed it with diluted iodine solution and kept him out of the water for a portion of each day but the spot has still grown. It's at the back end of his shell and is spreading slowly upward. ANY ADVICE?
THANK YOU
Fungal infections
Symptoms
Grey or white cotton-like layers on slider's shell and skin.
Causes
They develop as a consequence of poor husbandry (dirty water, lack of basking places or inadequate feeding)or/and in addition to other ailments.
Treatment
The turtle should be removed from the tank and should be kept dry and warm. Let the turtle in the water 2 times a day for 30 minutes to allow the it to drink and eat. Give the turtle a warm salty water bath 30 minutes a day. If you do not see improvement within five days, take her to a veterinarian.
Medicine
See if the white material rubs off easily (fungus). If so, use Fungus Cure (Aquarium Pharmeceuticals - available most tropical fish stores and pet shops) in the water. Also, apply Betadine solution locally to the white spots with a q-tip and keep out of water for awhile.
Dry them off, paint with plain Gentian violet and allow to dry. Coat with Newskin or Opsite and allow to dry. This forms a protective film over the area that is waterproof. Once dry put them back in water. Repeat every two days or so.
I don't know turtles but I found this. There's a reference to bacteria, but I lost it. I typed in 'white spot on turtle shells'. You'd understand this alot more than me. There was 'a thing' about don't feed your turtle cheese. Turtles have a weird diet.
It sounds like the white area is hard and not a fungal infection which would be fuzzy and/or soft.
Can you post a photo of the turtle? That would help a lot to see the shape, texture, position, etc. Shell white spots might occur if the turtle doesn't get enough calcium or Vitamin D. What does he eat?