My flagfin angel has pop eye. The eyeball itself is clear and looks normal other than it is pushed way outta the socket. What is usually the cause of this, and what can be done about it? Will he eventually die, or possibly make it thru it and be ok? I just set up a UV sterilizer last week and also was wondering how long it usually takes for one of these pieces of equip. to kick in and start improving the health of the tank.