(Hello all) Missing hermit crabs

[johnnyblackheart]

Great podcasts they are a great help! I’m new to this forum so I’m going to jump right in with a question.

Ok gang we have a mystery on our hands!

I just loss my fourth scarlet hermit crab! All four have just disappeared with no body to be found. I lost the first two scarlet crabs about 6 weeks ago I thought OK maybe the cycle was not fully completed (even thought the tests were good). The latest loss was two nights ago, and it happen like the others, saw him in his daytime hiding cave looked ok. Then in the morning he was back in the cave but I could not see anything claws hanging out and figured he was napping or something. Then today when the shell was still in the exact same spot / position I broke out the gloves and retrieved him and yep another empty shell

This time I removed all the rock work and nothing not even a piece of a claw now the kicker is I have 3 other blue hermit crabs in my sump who have been in there the whole time and are fine. Also I have a turbo in the main tank and 1 Astraea in the sump and 1 in the main tank and they are also fine.

Here is a snapshot of my last two water tests:

15 gal. main tank
5.5 gal. sump
20lbs of live sand
30+ lbs. of live rock

Date 1/17/2006
Time 9:40 PM
Temperature 76.6
Specific Gravity 1.024
pH 8
Alkalinity
Ammonia (NH3) 0.25
Nitrite (NO2) 0
Nitrate - Nitrogen (NO3) 0
Phosphate (PO4) 0.25
Calcium
Magnesium
Iodine
Strontium


Date 2/4/2006
Time 8:42 PM
Temperature 78.4
Specific Gravity 1.025
pH 7.8
Alkalinity
Ammonia (NH3) 0.25
Nitrite (NO2) 0
Nitrate - Nitrogen (NO3) 0
Phosphate (PO4) 0.25
Calcium 360
Magnesium
Iodine
Strontium


The water seems to be OK.

Could it be “Turbo the ripper”? Any thoughts, help, ideas will be appreciated….

[gwen_o_lyn]

Welcome to TR Johnny!!

Sounds like you could have a hitchhiker on your live rock that is looking at your hermits as dinner. You may wanna keep an eye out at night and look around. Do you hear a popping sound?

I do see you are showing ammonia in your tank- not the best idea to have critters when you see ammonia. Always best to fully cycle a tank before adding anything.

So what do you have planned for this tank?

[johnnyblackheart]

I often break out the flashlight and watch the tank and night just to see the goings-on. Other than some big ol’ bristle worms and a variety of pods running about. I have not seen or heard any unknown critters, but the possibility of a mantis shrimp has crossed my mind. Would there be any way to draw out a mantis shrimp into the open?

As for tanks plans, once I get my 175watt MH I’m going to keep some zoo’s some LPS’s and a goby.

[Rob]

not exactly sure what it could be.. more observation might be needed..
now, some thigns that might be related but cant say for sure...
temp was a bit low, not a lot but i would recommend keeping at least 78, preferable 80
salinity looks good, but the PH of 7.8 is quite low... it should hold steady at 8.2

how long has the tank been setup?

[Jimm]

Are their shells laying around? Or are the shells missing too. If they are there, are they in one piece or broken up. If they are intact it could just be the normal struggle that hermits go through to get bigger shells when they grow. If they are gone or broken they you might have a predator. I've never had to deal with a mantis shrimp but there are lots of plans for mantis traps on-line.

Welcome to Talking Reef! I hope this helps.

Jimm

[johnnyblackheart]

I am going to raise the PH of the tank as suggested. I know the temp is a little low, but I was waiting to see what effect the MH light would have on the temp. So I think I’m going to hold off getting anymore critters until I install the light. I also picked up a copper test kit to see if that could be a culprit. Thanks for all the input I’ll keep everyone up to date on my findings.

Also the are shells are intact, just no more hermits :(

[pham411]

ahh the imfamous mantis. watch out for these guys their pinch can break skin

[ghostbear29]

actually they are the spearers or clubbers variety. They really dont pinch. But they get the name thumbsplitters for a very good reason.. A guy here in Tucson has one and it cut threw his glove and lacerated his hand while cleaning the mantis tank! Mean but definately a cool pet! He fed it crabs and snails all the time. Also, If you found a bad crab or pest in your tank, he would take it and feed the mantis in his.

[JustDavidP]

It's also very important to provide a 'surplus' of differing shells for your hermit crabs. I had 4 different scarlets fighting for one single shell! Of the 4, only the LAST to survive got his way. The other three were pulled from the shell and dismembered!

Also keep in mind that different crabs use different shells. The abdomens of the many varieties are all DIFFERENT. Blue legged crabs tend to like the longer, conical shaped shells like those of the nasarius and cerith snails. Scarlet hermits and zebras are often sold in shells that look very much like "conch" but will use turbo and astrea snail shells as well.

In any case, differing sizes are needed too. With each moult, the crab gets larger and needs more 'room' for growth. If they do not have the appropriate shells to move into, they will die. Some are just eaten when they are out of the shell. Others will be so constricted in the old shell that they perish.

Dave

[Reefbaby]

At what point do they stop growing? Do they just go indefinitely? Mine hasn't seemed to have molted in over a year...he seems to be quite content in his little home, so I haven't put too much thought into more larger shells....

[JustDavidP]

I know that there is a certain, maximum size per species, but I don't know what that is. I had an unidentified hermit crab sold to me as a scarlet that molted often and ended up in a turbo snail shell about 2 inches across. I donated that big boy to the LFS.

D

[johnnyblackheart]

Well after looking at a bunch of things from water parameters to unseen predators, I have decided to chalk this one up to alien abduction, I figure they swooped in over night and beamed him right out of the shell.

I have been using this “down time” in my tank to makes some changes / adjustments to my 15 gallon. I put my remaining snails, and blue hermits into the fuge on my 55 gallon FOWLR. After some research I will be adding depth to my sand bed, not quite a deep-sand-bed but I believe will be better for overall tank health. Also I am working on installing my MH retro kit over my tank.

[Rob]

I have decided to chalk this one up to alien abduction, I figure they swooped in over night and beamed him right out of the shell.

those darn aliens.. lol :D

thanks for the update, hopefully after the changed things will go better.