Crab Manifesto

[Witfull]

many of you know, i dont care for crabs in a reef tank. many of the newer peeps here may not know why though, so,,,i wrote this post awhile ago and i thought it might help shed some light on my signature. ive been doing reefs and tanks for a long time. i have managed large marine stores, worked wholesale, and collected from the field. also i have been on the boards for awhile now and havwe read story after story of their evil exploits,,,,so without further adu....my manifesto of crabs.

ok seriously, crabs by nature are opportunistic feeders, many when young feed on algaes (mythrix). yes this can be beneficial to an aquarium, but remember that in the ocean there is a lot of room to move around. these young crabs will graze here and there taking their favorite lil bits and move on. in a confined environment they cannot do this. therefore they will be forced to eat more food in one area, thus they will look harder for something they really want. if this means pulling your prize Zo' out like dandylions from your lawn just to see if there is something good hidden between them,,,they will. if they find a tasty morsel on your sinuaria, they will think there is more, so they can dig into it trying to find it, regardless of the damage inflicted on the sinularia.

now these crabs are getting older, and bigger, their diet is changing, their bodies require more protiens, what has more protien than algae?...yup, flesh, now opportunity becomes a factor once again, if they can get the same protien from snatching up a snail and spending 10 minutes eating it as they would get from 2 hrs of grazing,,,,bye bye snail. if they find small fish sleeping (remember crabs are night active also) fish could very well be on they menu. i have even seen small holes in larger fish that came from a crabs eating on them while sleeping. (some tangs can be sound sleepers....the sea monkeys got my money)

so in my few deacdes of reefing i have come to the conclusion that crabs belong in the ocean, or on a plate, but not in a reef tank. even the most placid lil "oh he has never caused a problem" crabs, has a demon inside, the demon of opportunity, and sooner or later the moment will come, and for us when it does....its too late.

Crabs Are Evil

[Woodstock]

Hear, hear!!

[Scooterman]

I think crabs are so Cool!

[Warnberg]

Wit, do you feel ALL crabs are this way or what? I have some scarlets in my tank and am wondering if they are really worth the risk?

Thanks

[Gina]

We have had two different types of crabs in our tank.
1) Emerald Green (going for the bubble algae) didn't work!!
2) Sally lightfoot. They just looked cool.

I will admit that I had to take away a snail once from one of the Sally lightfoots but, that is the the only thing I have ever seen any of the crabs we have HAD do bad.

Our last crab died about 6 months ago or so and I have decided after reading alot of stories also about crabs that we shall remain crab free from this point on.

[Witfull]

ive said that scarlets are the smallest crab therefore offer the least evil,,,but they are still an imp of evil. some swear by them (cough Woody cough craig). but i personally dont want them in my tank. i like my snails in their shell and happy with out fear of eviction. but it is to each there own. oi juat want it to be told that they are not the savior of scavanging and algae control.

[Rougiem]

Excellent points Witty!

That makes me think though...How many other reef inhabitants are problems? Many more things than crabs can be problems even if they are deemed "reef" safe. One is confining all tank inhabitants to a smaller environment. It is not like their natural ecosystem. Just about every organism on the planet is an opportunist...Some are just more opportunistic than others. Experience and observation are the key in reefing, as you have mentioned witty as what works and what may not...Great stuff to chew on!

Cheers!

[Mad Mike]

Valid points but, To me it's about acceptable losses. Scarlet’s “peaceful reef safe" till they need a new home and that snail gets evicted. Evil crab or just programmed by millions of years of evolution? In the case of reds or blue legs they will only get so big before they no longer need to move. I solved part of this by accepting some of the losses and getting bigger empty shells and laying them in the tank. Also the snails that have survived are smarter, well smarter as snails go anyway It has balanced out now. I took more snail losses from the scarlets and red and blues then I did from the mithrax crabs. And reds and the like are supposed to be peaceful herbivores. Yeah they are till they need a new home. Empty shells fix most of that.

As far as oppturnistic feeding, very true but if you keep them well fed they are less likely to try and grab a fish, and some fish no matter how hard they try just can't be grabbed, wrasses for example.

I dunno I'm kind of accepting of the whole evolutionary thing some die some live. I have a ton of green mithrax and when the algae supply gets a little thin I toss in some seaweed. If they wish to eat meat there’s plenty around, not to mention pods and or worms and sponges.

And really if you have a tiny mithrax crab, let’s say even a large mithrax and he grabs a tang, you have to ask yourself what was wrong with that tang. Least I do.

Reef safe with caution.

I would be more leary of certain fish that nip polyps or large sponges then I would of a crab. There are so many beautiful fish that I'm tempted to start a fish only set up so I can have those Angles I long for.

[dobejazz]

I like my crabs they make me feel a little better about the excess food in the tank right now while I try to figure out how much the sun coral needs to eat. I too leave extra shells around and the crabs have not bothered snails my wrasse on the other hand ate both hermits and snails before i removed him from the tank. But I'm new at this so I could learn the hard way eventually (like I did with the "reef safe" wrasse the LFS sold me).
Kelli

[ReefDave]

I love my little emerald and porcelain crabs but,
Sallylightfoots can go to hell.
Big emeralds can go to hell.
those stupid red and blue fiddlers my LFS gets can go to hell.
random massive hitchiker crabs can go to hell.
little hermits that turn into monsters can go to hell(hairy red legs/zebra reef/mexican red legs/left handeds/anemone hermits anyone?)

so, in conclusion:
filter feeding crabs all allright
little emeralds are allright
scarlets red leg hermits are allright
little hermits are allright(except for blue legs!)
arrows are allright if you dont like little fish and bristleworms.

[DEA_MT]

i myself have come to this conclusion after countless incidents w/ different crabs. as for all crabs any time a snail looses it's footing and u don't discover him turned over within 5 seconds he's been eaten up. i've lost 2 pink skunk clowns and a skunk cleaner shrimp to a bastard of a mythrax crab in my 12g nanocube. and i've seen a sallylightfoot just start ripping up perfectly healthy zoos and start chomping on them!!! i've learned my lesson now. i'll just never restock any kind of crabs!!! death to the crabs!!!

[livingreef2004]

when i was a little wetter behind the ears than i am now i loved any kind of life i could find in my tank but after having crabs continually pick at the superglue to get under a frag i so carefully placed in the tank earlier of topple over a frag of zoa's knocking them face down onto my bubble coral i have decided to hate crabs too

[Little Luey]

I see your points but...
are not most animals in the ocean opportunistic feeders? won't a big fish eat a smaller one? I had a brittle star that ate a cleaner shrimp, crabs and snails. Also a sand shifter gobby that I saw more than once ambush my crabs and take them to his hole in the rocks. Even some clams will eat the algie cells in its mantle and coral will eat plankton.
So opportunity is what makes every living organism a meal. Don't hate the crabs for doing what they do, that is what they will do forever. The one thing we can do is choose our pets more carefully; as for me, no more brittle stars or big fish.

[Witfull]

yes opportunity is opportunity, but in an enclosed environment the opportunity is greater and we paid good money for the meals he is eating....thats why i hate them in a tank.

[Little Luey]

I could not agree with you more Witfull