I was hoping to put him in with my RES's (they're all roughly the same size about 4.5-5inches long (I have 2 RES's in a recently upgraded 65 gallon with an ATBA and a Fluval 406)). However if he's got a fungus than I heard that can spread to other turtles right? And I don't know too much about shell rot. I read that it can be cured but I'm not really sure how.
My RES's tend to ignore each other and, naturally if there were any issues with the introduction of this Map (i.e. fighting or anything of that nature) then this Map would have to find a new home (aka. my local turtle rescue). However I kinda doubted there would be any fighting issues, certainly not at this age and size anyway.
However, if this little guy has a broken shell that might complicate things severely. I do not have another water tank that I can set up for him. The best I could do would be a 10 gallon which is unacceptable in turtle standards.
I have no idea what he was fed or if he's even eating. I tried to brush off some of the algae (there was a LOT of it on his shell) with the soft side of a sponge just so I could access the damage but his shell is still really messed up. So I need much needed advice and I need it ASAP.

