Reptile & Amphibian Forums

I have what I believe is a pair of male RES, one of them has always been a little smaller. During the heating season the smaller one developed a white patch at the top of its neck right where the skin folds to allow retracting its head. It stayed the same for several months, then suddenly about 6weeks ago the spot bloomed until it looked almost like an anemone (with a huge lesion at its center like the mouth of anemone) I recently moved the duo to a bigger tank and souped up the filtration. Briefly he responded to an antibiotic pellet. But the biggerone has recently made him bleed by climbing on top of him. They have spent large portions of their time stacked one balancing ontop of the other since they were the size of pokerchips. They still do it while basking. They look sort of like those asian sculptures with all eight feet sticking out and up, resting on the flat of whoever's shell is bottom most. There's a question here. They have started displaying aggression behavior from time to time and the bigger one gorges, pushing the smallerone out of the way when they feed. The small one isn't eating minnows, but will eat most anything else turtlefoodish.
The smallerone is successful at intimidating the larger one most of the time, but is slower now so he gets scratched up.. So does anyone know what the very slowly healing thing on his neck is and should I seperate them during convalescence?

Yes, I'd separate the sick one. You can easily find some kind of betadine solution to put on its wound, but make sure it's safe. Keep it out of the water for periods of time, dry dock it, and apply some medicine.