emerald crab killing hermits

[jacrmill]

so i have recently found about 5 or 6 dead scarlet hermit bodys floating around my tank. I havent been able to figure out what it was until just now. I just walked over there and saw an emerald crab scurry away from the corner, when I looked closer I saw a scarlets body all ripped up.
so did the emerald kill my hermits? or was he just cleaning up the dead body?
My 29 gallon tank includes:
6 line wrasse
royal gramma
2 emerald crabs
used to be 10 scarlet hermits now its about 3
8 snails
45 pounds of LR
If you do think it is the emerald, any ideas on how to catch him?
thanks for the help

 

[jessica47421]

i dont know that it was the emerald, but if it was they arent really that hard to catch, just wait till he comes out front to eat then put the net in and catch him, that is what i did no problems at all.

 

[renogaw]

i'd point elsewhere.. do you feed your crab and hermits anything? how old is the tank--any clicking noises? do you have spare shells for the hermits to grow into? are you sure they are not just molts?

 

[jacrmill]

The tank has been up for about a year. No clicking noises. And I was told that hermits dont molt, so Im not sure. But I am totally sure that I have been seeing fewer and fewer of them. So, not sure if they molt, but im sure they are missing in my tank. I dont feed them anything specifically, but there is plenty of hair algae that they munch on. Also there is plenty of food that hits the bottom of the tank. I would think that would be enough....any ideas?

 

[renogaw]

they definitely molt, it looks like the thing that comes out of the eggs in the Alien movie line. if they do not have bigger shells to move into, they are insanely vulnerable, as their spiral body is not covered by a carapace, but is soft (hence the need for bigger shells).
emeralds won't eat hair algae (much) and hermits shouldnt. you need to supplement their diets with meaty foods. you could always drop some pieces of shrimp, clam, etc and let them feast once a week. you really shouldn't have food settling on the bottom btw...its probably why you have hair algae

 

[jacrmill]

thats exactly why I have hair algae, it doesnt really bother me too bad though, so I let it go. I am installing a sump this weekend with some chaeto, so that should help with that. i also have 2 peppermint shrimp, and they seem to be doing well. By the way I do have lots of empty shells of various sizes in the tank.
Doesnt feeding my clean up crew kind of defeat the purpose? arent they there to eat the food that settles to the bottom?

 

[renogaw]

in a way yes, it does defeat the purpose, but if you didn't overfeed you wouldn't have food settling. since you havent said what food you're feeding, just remember crabs dont eat most food we feed out in the wild, they eat nicely decomposing snails, fish, poop, and other inverts some will eat certain algaes, but not solely. i feed my sun coral and make sure my inverts get some good snacks at the same time

 

[jacrmill]

i feed frozen food, usually use zoplankton and a mixture of frozen brine, squid and other stuff.
Bottom line, with me overfeeding, I think we can agree they are not starving. My water has been perfect. My SG has been about 1.024. I am going to lower that a bit, but that should be ok too. Im just not sure what the problem is. I know you dont think it is the emerald, could I just have a territorial scarlett? I know I have plenty of empty shells, but could I just have a jerk? Or did my 6-line just out of no where decide to start killing them, but not eating them? It just doesnt make sense to me....

 

[jacrmill]

so I looked up some more info, and you are correct, it seems they do molt. sorry about that confusion.
How can I tell if it is a molt versus an actual dead body? most of the time, I just see legs, but maybe 2 times Ive seen the whole body intact with a little white on the end.
I hope its not the emerald crab, he is a fun guy to watch. Thanks again, for all your help

 

[renogaw]

don't lower your sg, inverts like it higher.
anything could be killing them, especially if you dont see them moving. I just swapped tanks and i never realized how many hermits i had (probably 35 in a 75 gallon). I see the little clawlike molt all the time, getting eaten by my sally light foot or emeralds, or even getting picked at by my fish as it floats to its resting point. point is, they are probably just molting and they are probably hiding. easy way to tell is plop a nice big shrimp on the sand out in the open and see what comes to feast

 

[mikmcgyver]

Emerald shouldnt be killin em. I have a couple of blue legs, 1 red leg and a green emerald. They usually never are near each other...

 

[jacrmill]

out of 10 that I added, i was able to count 5 last night. Thats not too bad, maybe a couple have died, and a couple were hiding. I think you are probably right....I wont panic yet. But im keeping my eye on that emerald.

 

[deltablack22]

Originally Posted by jacrmill
so I looked up some more info, and you are correct, it seems they do molt. sorry about that confusion.
How can I tell if it is a molt versus an actual dead body? most of the time, I just see legs, but maybe 2 times Ive seen the whole body intact with a little white on the end.
I hope its not the emerald crab, he is a fun guy to watch. Thanks again, for all your help
This sounds exactly like a hermit molt to me. They look exactly like what you would expect a dead hermit to look like, except a dead hermit looks more like a crab with a tail. I did have a picture somewhere of a molt but I cant find it, so heres one of the underside of a hermit crab. A molt will include everything that you see here and then a white fleshy material just after the body. Hope this helps.