Slaughterfish AI
It seems slaughterfish will only attack the PC if he is in the swimming animation. If the area is shallow enough not to have it, it will stand in place even if attacked or if the PC is so close it could attack.
(RM-2076 from redmine: created on 2014-10-29 by Mordimer Madderdin, , closed on 2015-01-09 by David Teviotdale)