Seahares can be very helpfull withany kind of alge, and they can release toxins when stressed, I have had mine for over a year, in a 125 gallon, with no problems. I have mine with triggers, a puffer, a wrasse, and they do not bother with them. They lay eggs, but its not messy, its just looks like a large pile of thick string. I have done plenty/lots/TONS of research on them, if you have any other questions, I would be more then happy to answer them. I love my seahares, they are very social, I would keep at least 2 together, they like to be in groups. BUT, I would find the problem, what is causing the alge and try to treat it, and you can feed the seahare alge strips, and mine even eat silversides.