a friend of mine had them, and yes they do. but it takes quite a bit of pestering and annoying them, like you practically have to take them out of the tank and fiddle with them to get them to do it. I have seen vids on youtube of people doing it.
I want one, was told they are salt water fish and its impossible to maintain a salt water tank here..no idea of its true or not since it was from a petco employee and we all know how awsome their information is