I have maybe...one hundred of them...I don't know. Their most troubling behaviour is a habit of collecting in large numbers on SPS during the daytime. "Group huddling" behaviour that blocks the light getting to the coral. Other than that, they've never been a problem. I don't know if they are doing anything particularly good or not....Food for the mantis, I suppose.

You know, starting up my new tank, this time around I said no blue legs. They ate all my snails in my last tank and just caused a commotion.

Now I've got a disgusting sandbed. A cucumber, brittle star werent cutting it - so I went and bought 15 last week. They are small, and are doing an OK job in a 137. Undecided if I will get more. They are excellent scavengers and quite hilarious to watch when FOOD!!!!!!!@@@ goes into the tank.

never had any issues with ours.

Yeah they are funny when food is dropped in...it's a mad rush, like they haven't eaten in a week.

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Thats what they are good for, getting the left overs that the fish missed. I find them to be snail killers as well, but as long as you have extra shells they should leave everthing else alone.

Aside from the 2 Astraea snails they killed, mine are fine. My favorite species of hermits.

blue legged hermits, fairy hermits and left handed hermits have never caused me problems. I love watching hermits they're allways real active :)

i have a bunch in my 24 gallon. probably about 6-8 blue legs and 3 scarlets. the scarlets are beautiful, but get bigger.

ive had very minor "hermit aggression". 2 of the little blue legs like to try to take the mysis from my favia, but the favia likes to send out it's feelers and tag the little guys. they learned pretty quick to steer clear of the favia at feeding time. one blue leg has setup shot under my frogspawn and keeps the branch and surrounding area very clean. personally i love the little guys. they also keep lots of feet on the rock and sand which helps keep the flatworm population in check. also helps stop algae growing.

Blue leg hermits are interesting creatures but I've cleared them from my tank as I find the snails do a much more effective job. Plus, they've dined on enough of my precious snails such that I was forced to make a decision to send them packing.