The substrate we are using is Critter Litter. The temperature at the basking side is 28 degrees, a little colder than usual as it is getting cooler here and the temp has dropped. The cooler side 20 degrees. I use a well named lighting and heating source from the company Reptile One. We use a UV tube for sun and a fan forced heating 50W for the heating. I guess I noticed the rash about 4 weeks ago. At first it was like a ring at the beginning of the tail but now the bottom of the tail (under the lizard) is a light pink colour where it should be white. We cleaned the enclosure hoping it would go away nut it didn't. Usually our lizard loves to eat. We feed it a variety of veggies and some meal worms. He loves feeding time. We also feed it a snail for a treat every now and then. We collect the snails from our garden but we keep them in a container for 3 days before feeding them to him. The temp has been getting colder as it is coming on Winter here in Australia.
What do you think is wrong with him?