Hey sin,
shhhhh- I put 2 brittle stars in my 37 gal with my clean up crew at the end of April right after my cycle, they're still fine (I didn't know either). Be sure to spot feed once in a while, at least once a week, fresh/frozen meaty seafood like shrimp, scallops, squid, octopus, that kinda stuff. Just soak the frozen stuff in some tank water to thaw, cut into teeny tiny pieces, put on a toothpick and hold it down to him...it's great fun!! Don't give him more than one piece a feeding though!!
Have fun sin.
Lisa :happyfish