Yes, that is the stuff. Put it on the affected areas daily for about a week and it should kill the fungus. If the fungus comes back, you may need to re-treat the tortoise every so often. Since redfoots like it rather damp, they are somewhat prone to getting lesions like those your tortoise has now.I had recently made a post of my tortoise shell and someone said it was fungus . I bought this ointment from the store and was wondering if it was going to be safe and effective before using it . Can anyone give me advice please @Tom