Zebra Urchin Crab  9/5/08 Hello I have a Dwarf Zebra Lionfish about 3" big. I would like to add a Zebra urchin Crab and would like to know if it would be safe in the tank. I have an urchin and I'm hoping that the crab will host it. The lionfish eats mysis and live ghost shrimp. Thanks. <This is a neat relation twixt the crab/urchin... but the Lion might well eat the former. Bob Fenner>

Compatible Clean-Up Crew - 08/30/06 I have a 30 gallon reef w/: Fish: 1 flame hawk, 1 false Perc Clown, 1 cherub angel Corals: tons of assorted mushrooms, hard (Frogspawn, candy cane), & soft (finger & umbrella leathers) Other: serpent star, live rock All inhabitants have been in the tank for at least 2-3 years (some 8+ years). <<Excellent!>> I have not added any livestock in a few years & it's time to risk rocking the boat & add something new. <<...with caution>> Since my current clean-up crew consists of just the serpent star I was looking at adding a package for general maintenance & to add some variety to the tank, but I know that the flame hawk limits my options. <<A bit, yes>> I'm considering some Astrea snails, <<Little bulldozers>> red hermits <<Opportunistic omnivores...and snail killers>> (I've found that the bigger ones hold up pretty well around the hawk) and possibly one or more of the following: - another serpent star: <<Excellent detritivore>> they are cool, but will another fight with the one I have? <<I have always found Ophiuroids to be quite compatible between both inter- and con-specifics>> - a Coral Banded Shrimp OR 3-4 peppermint shrimp: I know they likely wouldn't get along together, & that the CBS would have a better chance w/the flame hawk, but don't know how aggressive he would be w/other inhabitants. <<Can be very aggressive>> Or should I completely forget about any kind of shrimp w/ this setup? <<Normally, I would recommend Lysmata amboinensis and/or Lysmata debelius as the most beneficial (cleaners) and the least destructive of the commonly available ornamental shrimp.  But the presence of the hawk fish does pose a threat to these shrimp>> - One or 2 emerald crabs:  I think they would fair reasonably well w/the flame hawk, but don't know how aggressive they might be toward other existing/proposed inhabitants. <<Have been known to attack/kill fish>> Any comments on my plans are greatly appreciated - I'd rather be informed that something is a bad idea before anyone gets eaten.  Suggestions of other critters to add in place of anything on the list are also welcome. <<My opinion is to exclude the crabs (all are too opportunistic for my taste) and go with some snails (Cerith and Nassarius species get my vote) and maybe another serpent or brittle starfish.  The Nassarius snails and the starfish are excellent detritivores, the Cerith snails feed upon algae/diatoms without knocking your corals about or falling on their backs and dying/fowling the water>> Thanks, Kim <<Quite welcome.  EricR>>

Hermit crabs - algae Dear WWM: If you were to choose 5 species of hermit crab or crabs in general, for routine cleanup of green hair and filamentous algae in my reef tank, which would they be? I intend on having corals and want "reef safe" varieties. I live in Ft. Lauderdale and can collect hermits from the tide pools.  Can I use these?  If so, what species...blue legged, red legged, etc Thanks, Steve < I would do mainly red leg hermits.  Sally Lightfoots are good at eating hair algae also. Cody>

Re: Initial Clean Up Crew Thanks again.  How many snails and/or crabs do you think I would need initially? <None... please see WWM for input on such crews, selection> To refresh, it is a 440 gallon FOWLR with about 210 lbs of live rock, no fish in the tank yet.  The substrate is CaribSea Aragamax Sugar-Sized Reef Sand: 0.2 - 1.2mm diameter grain size. It is about 1-2 inches deep so I don't see much need for deep burrowers.  Since there is no fish, I guess the only food initially will be any debris off the rocks and coralline algae. <Yes. Bob Fenner>