I've been contemplating picking up a helfrich's goby... just can't bring myself to drop $180 on something that's 2" in size :P ....not sure that counts for anything.
We had an 18" Niger Trigger in our 220g. $80 fish... I guess that's rare. He perished, tho
We've also got a black banded shark in there as well - this was an extreme deal - the guy wanted $45 for two of them, but we only had the space for one so $25 for something that's typically $130+ each!
He's surviving! He eats everything that hits the bottom of the tank (which isn't much after the 9" faerie wrasse, 12" sailfin tang and 8" humu get their fill).
Here's a couple pictures of the little guy: