In the one picture it does look like tailbiting (blue with lots of red). It looks like he's chewing between the (not sure what the proper term is for fish) veins of his tail. Feathery ends are another good indicator of fin biting. I'm not sure about the other one tho, sorry.
For fin rot and fin biting the best treatment is lots of clean water. Daily water changes are advised. In the case of tailbiting this helps prevent fin rot from occurring. A high protein diet can help with fin growth, live foods if possible, or frozen (not freeze dried) foods.
Sorry to see he's tail biting, mine has done that a few times, it's so frustrating when you try to do everything right for him and they do that.