Could be fin and tail rot (Fins are usually folded or closed. Fins and tail appear ragged and split and may eventually erode to body of fish. Secondary fungal infections may occur). Or it could be stressed and bumping into live rock, or a territorial fish could have nipped at it. Melafix would be my suggestion if it worsens.
HELLO ElizaBeth!READY TO MEET YOUR FUTURE? Weird huh? Guess the chinese zodiac thing is right, we are soulmates maybe? Cant wait for Friday/Saturday, this is just too weird to ignore!