angelfish with wound

Question
My angelfish has a wound on his side....almost like a split in his skin.  I have treated water with Stress Coat and also used Metafix directly on the wound and in the water.
It doesn't appear to be infected but will not heal, either, and almost looks larger this morning.  He was not attacked and I don't know how this happened.   Ideas on how to heal this would be appreciated.  Thank You

Answer
Hi Carol,
Any sharp decor in your tank will cut your fishes' skin.
If this is not the case,an open wound can be caused by an anchor worm. These worms attach themselves to fish and cause an open wound. If not treated it can lead to a bacterial infection. I would use aqaurium salt for this problem.

Regards,
Chloe.