Spots on bottom of tortoise

[Tabathan3637]

Hello so I’m a new tortoise owner I have a red footed tortoise he seems to have these white yellow looking marks on the underneath of his shell can anyone tell me is this shell rot should I be doing something for him we did do the conifer test to it to see if it bubbles and it did not thanks for any input that could help!

 

[Yvonne G]

It's the start of a fungus infection. Temporarily take him off the wet substrate, dry and rub in some athlete foot cream

 

[Tabathan3637]

Thank you