Cumberland slider sneezing

[12kslr33]

My cumberland slider has been spending alot of time on his dock recently but my other 1 who is same age and size has been complete opposite, as normal really, the 1 who keeps staying on his dock keeps opening his mouth very wide every now and then and quite often makes a squeaking noise, for the first time today i heard him sneeze, it was like a human sneeze and it sent his head into his shell when he sneezed, can anyone help me with this as i dont know whether it is serious or not.

[Graham]

It's almost certainly RI and yes it's serious, separate them immediately and disinfect the tank and all equipment before putting the other one back in, then put the sick one in it's own tank with raised temps, water up to 26-27°C, basking spot 35°C, heat on all night, and get it to a vet for antibiotics asap.

You'll need to keep a close eye on the other one too, RI is infectious and it's quite likely it has it too but you may be lucky, of course you'll need to observe strict quarantine between the two washing your hands with antibiotic soap and disinfecting any shared equipment.

You'll need to keep them apart until it's fully recovered which could take several weeks, so you really need a full second setup.