Crab safety

[Crazed]

Hi guys,

I'd really like to get some crabs for my 75g tank. I know they can be incredibly destructive if they're too big in number, so I'd like to get only ONE emerald crab and ONE hermit crab. I've had my eyes on the emerald crab since day one - plus, I have bubble algae. I also have several large snail shells from snails that died, so I've recently thought about getting a hermit crab as well.

However, I've heard stories about these guys attacking small FISHES even! How much does this happen? I won't be very upset if they eat a few snails, but I'll never forgive myself if they kill my fish. Is that even possible? Has anyone seen this happen? I have a gramma, an Allen's damsel, and two Ocellaris clownfish. I've also got a brittlestar and a cleaner shrimp, which have always been great sports. I won't be getting any fishes that are smaller than that in the foreseeable future.

I've been presuming since my tank-to-crab ratio will be so large, that I'll be able to keep them well fed enough not to do anything like that. But, do they attack fish anyway? I thought the emerald crab and some species of hermit were pretty much herbivorous. I remember I had similar concerns with sudden carnivorousness with my large brittlestar too, but my fears never came to pass.

I'd really, *really* like to get at least one of these guys, so let me know what you think. Thanks!

 

[Glaucus]

Crabs can be destructive. But that's about hitchhiker crabs. These crabs are supposed to be reef safe meaning they don't pinch corals, attack each other and stuff. How are they going to hunt fish?

There are different kinds of crabs and hermit crabs. I heard you should have one small hermit crab a gallon, ignoring snails.

I think you should be more worried about your brittle star then any hermit crab. Especially when they get big.

Hermits aren't supposed to eat snails. But big emeralds you can expect to eat snails. And it may also go after the brittle star.

Paguristes cadenati is the least aggressive reef hermit. Clibanarius tricolor is the best algae eater of all the reef tank hermits. If you give them spare shells they should behave properly. If you are worried, don't get an emerald crab. They are much less safe around corals then these hermits.

If you have bubble algae get something that eats bubble algae. Emeralds are supposed to eat it. Not sure which hermits do. Maybe your best bet it to add a small emerald crab and remove it when the bubble algae is gone.

 

[Crazed]

How are they going to hunt fish?

That's why I had doubts about these stories - however, I heard they can attack small fish at night if they "sleep" towards the bottom.

I think I'll want to keep the emerald even after the bubble algae is eaten - I like very much how they look. I'll make a decision based on how big he gets.

Thanks for your post, it was very helpful. Anyone else have any opinions on any of these matters?

 

[Glaucus]

It seems emerald crabs may eat fish if they are really big and really hungry. But if you buy them small this shouldn't happen. You can find these stories using google. But then there's always people that claim the fish was sick or already dead, crab wasn't a green emerald crab, etc. So it seems emerald crabs have a risk involved. But the usual hermits are entirely different. But they won't eat all your bubble algae.

 

[pugcrush]

How big is your tank? From the sounds of it, you don't have any hermits in your current CUC?

 

[Crazed]

How big is your tank? From the sounds of it, you don't have any hermits in your current CUC?

That's right. Right now, all I have is a cleaner shrimp, a brittlestar and two snails. My other snails died from another issue I've solved, and I'm ready to rejuvenate the CUC.

And my tank is 70 gallons, 3' length - I said 75 earlier, but I don't know what I was thinking.

 

[mmenz22779]

See my thread on this topic and what happend to $60.00 worth of featherdusters

http://www.reefcentral.com/forums/showthread.php?t=1817191

 

[Konolua]

Only hungry crabs are guaranteed problems. If you keep it well fed (either by hand or otherwise), you should be fine.

Although, as stated earlier, they are opportunistic and if a fish rest near them, they usually swing out of defense, but a piece of food, alive or dead, in a crabs claws is dinner.

 

[mmenz22779]

I had 2 emeralds (a big green one and a big red one) left after my issues (see other thread) and yesterday while feeding the tank, I watched (should have video'd it) the these guys grap my hermits and start attacking them for food. I also have 1 small emerald that I missed when catching the others (again see previous thread) and he minds his own buisness.

what I am trying to say is the big emeralds seem seemed to be really aggresive. I since captured both of my big ones and traded them in for featherdusters.