Let's Talk About ~Crabs~

[Angelscrx]

Lunchie Welcome to Reef Frontiers.

 

[robbiej]

Side bar.

What's an acro?

 

[NaH2O]

Acro is short for Acropora species, which is a type of SPS (Small Polyp Stony) coral.

 

[CarlaW]

I usually add crabs, the micro blue legs from Reeftopia about once a year. They do a good job of cleaning up, and unfortunately, munching on snails. Oh well, I'm sure it happens in nature, so I'm not real worried about it. I also have some scarlet legs, I like them for their color. They aren't real active during the day, but a flashlite will catch munching detritus and other goodies that help clean up the system.

 

[lunchie]

Gobie,
Thank you...I looked up the FoxFace Rabbit and he is gorgeous and now added to my "want" list! Is there any special care or problems you have had with him? My tank is only in its 5th week so I don't think I can add one yet?? I have a 75g tank, with Live Rock, and crushed coral with shells. See my photo gallery. However, I can't find anything on the sallylightfoot, do you have a link or maybe the scientific name for it? Thanks again,

 

[lunchie]

Charlie,
THANK YOU :eek2: I agree with you completely. Though I am new to this forum and this hobby, I love my little emerald crabs...

They do a good job of cleaning up, and unfortunately, munching on snails. Oh well, I'm sure it happens in nature, so I'm not real worried about it.

I have learned a great deal from this forum in just the couple weeks I have been posting! I just want to say thank to everyone!

 

[CarlaW]

Welcome to our little chunk of reef, hope you enjoy it here!!

 

[NaH2O]

lunchie - here is a link to a picture of Sally Lightfoot Crab. Check out our sponsors for them. I know Premium Aquatics, and Marine depot have them, but have a look around, for pricing, if you are considering them.

Has anyone kept an Arrow Crab? They kind-of give me the creeps. The Arrow Crab seems to be a popular specimen. What I've read is they are good for killing bristleworms, but will also kill small fish and other crustaceans. I wonder if you keep them well fed, how much damage they will do in a tank. Or, are they one of those critters, where you sit back and say, "What was I thinking??".

 

[MikeS]

Has anyone kept an Arrow Crab? They kind-of give me the creeps. The Arrow Crab seems to be a popular specimen. What I've read is they are good for killing bristleworms, but will also kill small fish and other crustaceans. I wonder if you keep them well fed, how much damage they will do in a tank. Or, are they one of those critters, where you sit back and say, "What was I thinking??".

I kept them in my FO days...pretty neat, but I don't think I'd put one in my reef, especially with my DSB, since they love to munch on worms and such...I can only guess on how they would do with corals, but in my FO tanks they would eat pretty much anything that they could get their little claws on....

Mike

 

[Maxx]

Nikki,
I need to find out where he story came from...(Mike Palletta maybe??) but I read where someone had an Arrow crab that harpooned a Royal Gramma with its long rostratum, (nose), killing the fish and eating it. I've never seen that behavior before, but its quite a mental picture.
I know they will also eat feather dusters.

Nick

 

[NaH2O]

How about some nasty hitchhiker crabs. Here is one that was observed at night pulling mini brittle stars out of the sand and munching by the claw full. Once it started coming out during the day, it was time for this crab to take some snow ski lessons. In order to remove it - I tried pouring club soda & freshwater in the hole, nothing helped (even poured it directly on the crab). Ended up taking a metal skewer and coaxed him out of the hole entrance by pushing him from a hole above.

If you are curious about how to identify crabs here is a link to an article that shows some basic shape characteristics, along with some other good information: Crabs by Ron Shimek.

 

[MikeS]

Man, that's a nasty looking monster you got there Nikki :lol: Did ya give him a nice new home in the toilet bowl? :badgrin:

I remove hitchhiker crabs on sight, I don't even give them a chance to demonstrate their innocence or guilt...I've just caught too many of them snacking on my expensive polyps late at night....If I can't catch them, I try to find out where they are hiding and cook 'em with boiling RO water in a turkey baster...

MikeS

 

[NaH2O]

Yeah - she was a nasty one. I was fortunate enough to understand what the crab was saying, and she said she wanted to go in a snow drift.

 

[CarlaW]

There ya go, unleashing strange critters into the Indiana wilds. What are we gonna do with you???

 

[Maxx]

Well I dont think I'd play in snowdrifts with her.

Nick

 

[MikeS]

Ok...how about hermits?....lots of people have hermits in their tanks...how are your experiences with the different species of hermits?

I've had a few different hermits. Blue legs, red legs, ect....I ended up removing all except the scarlets. So far the scarlet reef hermits have yet to prove themselves guilty of anything. But I don't have very many, 3 or 4 of them in my 55. I know that many people put a large number of hermits in their tank as part of a "clean up crew"...could this overcrowding force them to look elsewhere (our expensive corals) for dinner?

MikeS

 

[wrightme43]

Good point on the overcrowding. I had never thought of that. Food for thought. Steve

 

[NaH2O]

Mike - I agree. Perhaps the crabs feel a population density pressure, and therefore feel the need to grab whatever they can to eat. I only have 3 scarlets in my 120, and so far, they haven't done anything bad yet (although I'm keeping a close eye on them). I posted this quote earlier, but think it is fitting in this part of the thread, too. What do you think about this quote from Dr. Ron (link on the first page)? I find it interesting that he points to the blue legs as benign in small numbers, however, when hobbyists talk about hermits blue legs seem to get into the most trouble.

The masses of hermits that folks seem to be having in their tanks create a decidedly abnormal situation, as such herds are simply not found on most reefs. Their crawling over animals such as corals and sponges is abrasive and destructive. They also remove food from sessile animals such as corals. Additionally, hermit crabs are at least partially predatory and the bigger ones are particularly a problem in this regard. Some of them are significant predators on small snails, other small crustaceans, and each other. When folks see hermits gleaning materials from the rock surfaces, they are seeing the hermits pick off small animals as well as small plants. This results in an abnormal surface that has only the animals and plants that are hermit crab resistant living on it. Additionally, at least some of them appear to be predatory on some of the worms living in the sand, and I think this is decidedly a problem.

Upon the removal of hermits from my reef (and their replacement on the sand by Nassarius snails as scavengers) I have noticed a significant new growth of smaller polyped animals, as well as small feather duster and other tube worms. I have not noticed an increase in algae. Basically, I feel like the hermits are an unnecessary complication in high numbers. Some species I think don't belong in an aquarium under any circumstances, but others like the small blue legs are probably benign if there are only one or two in a system.

 

[Witfull]

raising the banner high,,,so all can see,,,Crabs Are Evil!

 

[mbindon]

Nikki,
I need to find out where he story came from...(Mike Palletta maybe??) but I read where someone had an Arrow crab that harpooned a Royal Gramma with its long rostratum, (nose), killing the fish and eating it. I've never seen that behavior before, but its quite a mental picture.
I know they will also eat feather dusters.

Nick

Sorry to drag up an old thread, but I'm having some crab issues at present. I've got an arrow crab that killed my sleeper gobie. I've also got 2 emerald crabs that I caught picking at my new Zoo. So right now I'm trying to decide whether to get rid of all three of them or not.