i have had several. as far as when they die they will kill your tank. have not had it happen to me. if this were to happen the sea hare would have had to have died from a sudden and violent way. only when frightened do they release the ink, that could kill a tank if the filtration was not up to par.
would i recommend one to someone, prolly not. they have an insane appetite for algae. one of the ones i had ate sargassum stalks like speghetti. would just slurp them down. it is very difficult to have enough algae in the tank for them to eat. i used to move one between two systems. eventually it cleaned both out and wasted away.
i had it for over a year.
G~
