Hey I red your post.
Be warned. I got a Sally Light foot (Tiny one the size of a quarter). They will hide and disappear eating algae like nuts (and will clean your tank Algae free).
I thought mine was dead for 6 months then he appeared one day. A MONSTER. Size of a BASEBALL SOFTBALL. We all freeked. Kids did. He was fun to watch him come out, because he ran out of algae. Then he started going nuts, like climbing the glass to scrape any algae he could get. He was starving. He eventually starved and died. But I hear they might attack your fish and rip apart soft corals. Mine never did.