good and bad

[Delphinus]

I'm a little unsure what the actual answer is. I don't think that they do.

From what I understand some species emit an inklike substance when harrassed, but I read on RC where people have had this happen without subsequent tank crashes. And not all species may do it?

I think the real risk is ... what do they eat after they have cleaned out your tank of hair algae?

In searching RC for a better answer to this question I came across a few mentions of them eating caulerpa. SCORE!! I'll let you know if mine does anything with it (he's in a different tank at the moment).