Snails and crabs

[duanen]

I have had 2 hermit crabs and 2 turbo snails in my tank for over a month and noticed they are not very active. I can see the crabs move their legs but they have been sitting on rock in the same location for days. My snails haven't moved in days so I pulled them out and had them in a cup of tank water, they sucked up to the cup so they are alive. Put them back in the tank and still no movement in days, any ideas?

 

[mr. limpid]

You'll find that creatures do what they want not what we want. They must have enough food in the area that they are in if not they would move. What size tank is this, you may want to add more. I suggest going with either or not to mix snails and hermits, hermits tend to eat snails.

 

[duanen]

It's a 36 gallon bowfront. Just got home from work and found one hermit crab dead, he was out of the shell about 2 feet from it. My other crab is still sitting on rock but is moving. The 2 snails are still in the same spot they have been in for days, seems the only time the move is when I move them doing a water change. I have 2 Ocellaris Clowns, a Pajama Cardinal and a Scooter Blenny in the tank and they have no issues.

 

[mr. limpid]

Two things, check your nitrates, inverts do not handle high nitrates also what type of salt mix do you use. Crabs and shrimps need iodine to help them molt.

 

[duanen]

My nitrate reading is 20 PPM and I use Instant Ocean salt. Is 20PPM too high for them?

 

[saxman]

Your crab may have molted...the cast-off cuticles look an awful lot like a crab without the shell. In the future, give them a sniff...if it's a cuticle, it won't smell bad, but if not...WHOAH. This also works with snail shells you're not sure about.
Turbos aren't the hardiest snails in the world if they're not established, so they may not be doing well in general. Unless you have a hair algae problem, I'd leave them out of the mix for now.
Finally, are you feeding your CUC? Is there any food growing in the tank (algae)? If your tank isn't providing food or ENUFF food, you'll want to feed your CUC so they don't starve away on you.

 

[duanen]

There is plenty for my CUC to eat. I would have to agree with Mr. Limpid that if they were hungry, they would be on the move looking for food. It wasn't a molt I know for sure. It's to the point where the only thing cleaning any algae is me. Is 20ppm nitrates too much?

 

[saxman]

20 ppm isn't nuts for a FOWLR (I guarantee our tanks are higher than 20 ppm), but it's high for a reef. Some inverts do fine at these levels, others don't. Often, it has to do with the condition or species of the invert. For instance, IME, Turbos are hit or miss, depending on where they're collected (mexican Turbos seem to like cooler water, and are a bit more sensitive IME).
I'd try some other snails, ans maybe even try another source for your snails. Look into Nerite, Astrea, and Trochus. If you get Astreas, be sure to either let them "suck onto" the tank panel or sit them right side up on the bottom so they can get their foot under them, as these snails can't right themselves very well, and often become hermit food (once established, they're fine).
HTH

 

[duanen]

I'm going to get some different snails and see what they do. I'm still wondering about the hermit crabs though as they were also doing very little. I had three emerald crabs which were doing great but I had an issue when I found one hovering over a dead clownfish. They next day I had another dead clown with a crab eating on it so I got rid of the Emerald crabs and haven't lost a single fish. I did observe a clown hovering over top of a crab when my light went out and witnessed the crab grabbing at the clown, don't know if the crabs were the cause of the fish croaking or not. Just seemed odd that the replacement clowns for the two that died are thriving since I got rid of the Emerald crabs.

 

[saxman]

Crabs are opportunistic omnivores, and if they don't find enuff food, they'll start on your fish. FWIW Mithrax crabs often tend to go after fish once they get some size on them, regardless of how much food they have.

 

[mr. limpid]

I agree with saxman 20 nitrates isn't bad for fish only tank CUC should be fine under those conditions. Hermits life span is about 2 years give or take a year. Sometimes they just have a bad molt and die because of it. I basically add a new CUC every two to three years to my tanks.

 

[duanen]

I'm going to get a few more snails and crabs and see if I have better luck. If not, I guess I'll be my own CUC. Thanks for the help!

 

[mr. limpid]

I personal don't like mixing crabs and snails, because crabs will kill snail for there shell and for food. I would go with one or the other, the only crab that I've seen that didn't kill snails is the emerald crab (good crab for algae on rocks)

 

[fishman7663]

All crabs and snails are not the same. I have the Astrea snails and they tend to move around, but they do hang out at the top of the tank a lot. Although, I am not sure what happened, I was looking in the tank one day and noticed a hermit crab roaming the tank in an Astrea shell. Not sure if he killed him or the snail died and the hermit just ate him and confiscated his shell.
I also have an emerald crab that, when a fish gets close, he raises his claws but for the most part, he leaves everyone alone. I do make sure he gets enough food though. I feed him some seaweed every few days.

 

[duanen]

What is more beneficial to your tank, crabs or snails?

 

[flower]

Quote:
Originally Posted by DuaneN http:///t/392970/snails-and-crabs#post_3493484
What is more beneficial to your tank, crabs or snails?
Snails....crabs are ornery, they often kill the snails for their shells and when they get large enough bother the fish. Hermits do a really good job on cleaning brown algae off the rocks, but snails if you keep a variety, will keep even the sand sifted and eat uneaten food, keeping the tank nice and healthy (nassarius) without depleting the fauna. Cerith and nerite snails get the slime algae. Mexican turbos I believe (not sure) eat hair algae too.

 

[mr. limpid]

+ one on Flowers comment. And to add to this both crabs and snails have different types to handle all the algae and ditrus problems. It is up to you which type (Snails or Crabs) you want roaming around in your tank.