Hey guys. I have recently purchased two juvenile Murray River turtles 12-13 weeks of age. I currently have them situated in a 4 ft tank with 40 watt UVB light. I have had the turtles for one week and noticed that one of the turtles has developed large white patches across the top of their shell. as I am a novice I am unsure whether it is shell rot or what. I am really concerned as the other turtle seems fine though I have yet to witness either of them basking under the light/ out of water. I have tested the pH 7.6 kh 146 gh 386 I have fed them juvie turtle pellets so far. they seem to enjoy eating them though I am yet to give them anything else daily. I have feeder fish (barbs) in the tank with them along with live plants. Please help me so I can get help if needed. Will try to upload photo of shell and tank set up. Thanks.