<a href=showthread.php?s=&postid=7776221#post7776221 target=_blank>Originally posted</a> by traveller7
IMHO it is most likely unhappy with something in the water. Either an additive, or a build up, or missing something, or a day/night fluctuation, etc., etc.
There is also the chance it is unhappy with the diet, but I would expect the tentacles to be shorter if that was the case.