I have three of these and don't mind them just make sure everything is glued down. They are great algae eaters.

My urchin eats soft corals: toadstools, Xenia, anthelia and his favorite is zoas. Must feed him nori every couple days or he will eat everything...

any hermit crab. they have a preference for snails and when they run out of snails they just kill each other and have no interest in eating any algae whatsoever.

+1 Hate the little buggers!

I have no idea what the hermits eat in my tanks but they don't eat enough snails in my opinion :lol:

The only good crab is a porcelain crab in my opinion and even they can cause problems so no more crabs period.

Green death brittle star, it never had a chance to eat any fish but it was a bad impulse purchase that now lives in my sump.

Any kind of anemone (including tube anemones). I've only had a couple problems but they arent a good long term member of a mixed reef.

Turbo snails because they become too large and clumsy.

Rock boring urchin because mine kept eating the silicone holding the tank together. It too now lives in my Rubbermaid sump.

So what I've read out of this thread is that these critters seem to all behave differently in everyone's tanks (no surprise I guess) :-) Just like that "hit-and-miss" fish (aka, flame angel, etc..). You can never know for sure how they will behave in your tank. Save for a mantis shrimp incident a long time ago, I haven't had any problems with any inverts that I have purposefully put in my tank. In fact, I love inverts and how they interact with one another. My list includes starfish (red reef, lenckia), an urchin, an army of hermits, 4 skunk cleaners, 2 fire shrimp, 2 peppermint shrimp, 3 sexy shrimp, acro crabs, a Porcelain crab, snails of various sorts. Heck, I even enjoy just sitting there watching abalone craw across rock work. I know I'm weird like that. Those little buggers are amazingly fast though... sometimes I think they race.

My anenome crab seems harmless enough, just stays in the anemone all the time.:biggrin:

I had two halloween hermits that got very big and aggressive. They both killed my counches and stole their shells. One went back to the LFS the other met his match with a blue legged hermit with a killer right hook.

+1 :biggrin:

I got a cool orange/red legged, large (fist sized) hermit crab that ate my all my lil crabs and then catch him eating my starfish live! Bastard! :sad: