Killer hermit crab

mommahen

New member
Do you think a little hermit crab (part of a CUC) will kill a conch to get his shell??? Pretty sure this happened in my tank. It is suppose to be a red legged hermit... trying to get a pic because he doesn't look like the others and now he is happily roaming the tank with his shiny new conch shell.
[emoji35] I liked that conch!!! He was very active until this dang hermit started chewing on him. Guess he could have just died? Or was it a homicide??


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Do you have other empty shell inside the tank? They generally only kill a snail if they cant find any new bigger shells. They also change shells if their shell is too old.

If there are other shells, the snail probably just died, hermit ate it and deiced the new shell is too good to pass on.
 
I banned all crabs 17 months ago as I am not an expert on the thousands of crabs, but all are opportunists. Since the ban, I have not lost a fish, a shrimp, a coral, not even a snail.
Crabs do little as far as CUC, excellent water goes way farther, too much of a risk...

Don't be fooled by LFS "this is reef safe"
 
Yep, I'm thinks a ban might be in store for my tank too.
Little turd!
We have extra shells, but none the size of that conch shell. The hermit went from a shell the size of my thumb nail to a shell the length of my middle finger!!!


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Yep, I'm thinks a ban might be in store for my tank too.
Little turd!
We have extra shells, but none the size of that conch shell. The hermit went from a shell the size of my thumb nail to a shell the length of my middle finger!!!


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Wait what? That is not a red legged hermit. They dont get big enough to occupy a shell size of your thump. It is a hermit that is probably not reef safe.

I never head a hermit to kill a snail.
 
Wait what? That is not a red legged hermit. They dont get big enough to occupy a shell size of your thump. It is a hermit that is probably not reef safe.

I never head a hermit to kill a snail.

Mine loved escargot and walked around with a clownfish which it caught with its claws from the underneath of the belly. This is likely because there is very little uneaten food in my tank, so when push comes to shove.

Crabs are certainly OK for those who possess the knowledge of which are good and which are not, I hoping many of us would agree that most will eat what they can catch. In any event, I want my tank inhabitants to thrive and not have to be concerned about marauders, and after more than a decade, I still am not sure.

Maybe the ban is unwarranted, but it's appears to work for me.
 
Mine loved escargot and walked around with a clownfish which it caught with its claws from the underneath of the belly. This is likely because there is very little uneaten food in my tank, so when push comes to shove.

Crabs are certainly OK for those who possess the knowledge of which are good and which are not, I hoping many of us would agree that most will eat what they can catch. In any event, I want my tank inhabitants to thrive and not have to be concerned about marauders, and after more than a decade, I still am not sure.

Maybe the ban is unwarranted, but it's appears to work for me.

I think the main issue is people keep too many of them. I have maybe 7-8 hermits ( 4 red legged and remaining blue legged) and one emerald crab in 150 gallons. They bother nothing but algae. But crabs are opportunistic and if they starve, what do you expect them to do? I would also eat a lot of things I would normally not want to eat, if I was starving :). For instance, although reef safe, tangs can also develop and appetite for corals if they are not fed enough.

I think crabs do some essential work in a tank that no other inhabitant can do. Emerald crabs are terrific algae eaters and are capable of removing hair and bubble algae that snails and fish cannot remove. Their claws allow them to rip algae from thigh crevices that snails and fish cant reach. Hermits are dual function in a way that they can eat both algae and detritus. They are also very good at keeping the sand white. My red legged hermits spent most of their time cleaning the sand and tuning it over. Most snails for instance wont touch any complex filamentous algae of any kind unless it is mown down, they like film algae or algae that is mown down. You need hermits (or emrald crabs) to mow down the filamentous algae for snails to scrape of the remaining base.

Another benefit I encountered is; hermits flip snails that are stranded. Yes, strange as it sounds, I have seen in multiple occasions that hermits will flip an upside down snail. They probably do it to check out the shell or to check if something is under the shell (since they also move around small pieces of rock to check under), but end up flipping the snail back on once they realize there is something inside.

If you check the claw shape of reef safe crabs like emrald and blue or red legged hermits, they all have spoon tipped claws. Those claws are ideal for eating algae, they are less than ideal for catching anything that can move. It would be like trying to cut a raw steak with a spoon.

For hermits another important factor is available shells. Just because there are empty shells dont mean hermits will like them. They have certain preferences when it comes to choosing shells. So it is important to keep a verity of different shells. Some wont use shells other than what they are looking for. For example, in the ops case, I think the crab he has is something like a halloween hermit( since that is one of the few thumps sized hermits and not reef safe), which wont use anything but conch shells. In the same way, some prefers conical shells while other like round shells. I probably have at least a hundred shells laying around the tank, remaining from the snails I have kept over the years. I have never removed a snail shell from the tank and since I have a breeding population of snails there are many shells.

Imo, nobody needs 1 hermit per gallon or per 2 gallons or even 5 gallons, unless you are going to specifically feed them. You would need no more than 1 hermit per 20 gallons and for emeralds it is perhaps one for 40 gallons.
 
Far enough and well written.
If your going to manage them, I fully agree, this can be beneficial.

For me just a personal thing....since I was a witness to the attacks, I wanted to see if there was another way to manage the algae

When I spent time really understanding my water, nutrient, and lighting balance, I had no job for the crabs....so it was a why take the risk attitude.

I spend about 5 minutes a week to hand pick a couple of pieces and my mix of snails and gobys, and a lawnmower keep everything in check.

Sometimes I think new hobbists believe that a CUC is an must, rather, I believe it's an option.

BTW....your posts are always good reading and right on point!
 
Well I really think this was a mishap in the CUC. I know it is not a red leg, I'll get a good pic and see what you guys think.

I bought my CUC early, and the smallest package I could find. I have a 90, I got the package built for a 55. NOW I realize i should have just purchased individuals. Live and learn I suppose.

I do supplement feed the crew because it is not a mature tank and they took care of the algae i did have in a hurry! I give them wafers, lettuce, and frozen cubes (for the fish, they get the extras). I just think this guy was in the wrong group of snails. I had 2 bags (I blue leg hermit bag and 1 bag of snails) that all were DOA. I didn't replace, thinking what I had was enough to start with anyways. LA gave me a credit.

I'll probably just get this guy out and watch the others. He is growing awfully quick!! I'll get some pics!! Curious to see what you think he is!

Learning some interesting things about these little creatures, that's for sure!!



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I think the main issue is people keep too many of them. I have maybe 7-8 hermits ( 4 red legged and remaining blue legged) and one emerald crab in 150 gallons. They bother nothing but algae.

Really? I have a mix of about 15 blue and scarlett legged Hermits and three Emeralds in my 90 gallon and they don't bother any of my inverts or fish in my tank either. I think there's a turf war going amongst EACH OTHER though. LOL! And if anything, my Pakistani Butterfly and Aiptasia Eater keep harassing them! LOLOL!
 
Okay, getting a good look. I exaggerated on his original size. He was the biggest of the hermits I got. All of them are the size of my thumb nail, except him. He was a little bigger. Here are pics of the shell he ditched to the conch shell.
Then below is a pic of the demon himself. I turned him upside down and got some close pics. Never posted pics, let's see if this works!

f25a7fd0aeb6f79d20eb807ac4db5f15.jpg
840ca95787c80a42a4595d00ccb64050.jpg
c13e9a2787c87dbd4908c9a781d6355c.jpg



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Clarification
I received
1 bag of red leg hermits
1 bag of blue leg hermits (all DOA)
1 bag of Mexican turbo snails (all DOA)
1 bag of cerith snails

Can't remember how many were in each bag, but you get the idea



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That’s not a red leg. I’m not sure which kind it is, but not a red leg. I’ve been doing this for 16 years or so and have had many hermits. Some kill snails for shells. Some develope a taste. Some leave them completely alone. I have even had a few that killed snails for fun. Never even tried their shells. I recently had some in a lionfish tank and I guess they weren’t getting enough to eat because they ate his side rays off of his fins. Hermits can be jerks for no reason. They’re crabby, so to speak.
 
Okay, getting a good look. I exaggerated on his original size. He was the biggest of the hermits I got. All of them are the size of my thumb nail, except him. He was a little bigger. Here are pics of the shell he ditched to the conch shell.
Then below is a pic of the demon himself. I turned him upside down and got some close pics. Never posted pics, let’s see if this works!

f25a7fd0aeb6f79d20eb807ac4db5f15.jpg
840ca95787c80a42a4595d00ccb64050.jpg
c13e9a2787c87dbd4908c9a781d6355c.jpg



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I have no idea what that is, But just based on the claws, it doesn't look reef safe. The claws are like scissors, rather than spoon tipped, that crab cant collect algae. Also, based on its flatted abdomen and the fact that its previous and current homes were conch shells, it would probably only use conch shells.
 
Crooked Reef is right, Mommahen -
That's NOT a scarlett or red legged hermit crab! Hermits DON'T have white spots on their claws or legs!! The crab you posted in your pic DEFINITELY looks predatory. JMHO.
 
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