Just watch for white fuzz during the healing process. Saprolegnia is common opportunistic fungus on the tails and discs of rays. If you see this, which is unlikely but possible, you will probably need to treat. 9/10 times this resolves itself without any issues.
The adults never seem to bother him but it looks like he was after a free meal. He was swiftly moved to another tank. The white part did fall of and seems to have healed fine... Just as all predicted 
