Hermit Crabs Dying

[awtank2017]

Since starting my 24gal Biocube, I have had a total of 10 hermit crabs. I initially had 3 along with a blue tuxedo urchin and two of the crabs died off within a couple of weeks. Then I purchased 7 more along with 5 turbo snails. A couple weeks later we added 3 corals, followed by a Tongan snail and two fish. I have now lost all hermit crabs. Corals are doing great, fully extended. Fish are doing well. I am feeding frozen brine shrimp 3 times per week and feeding corals (just adding to tank not spot feeding). Not sure if there is not enough algae or why only the hermit crabs are dying off. Here are the tank parameters:

Ammonia, Nitrites, Nitrates, and Phosphates: 0 ppm
pH: 8.22 (lowest it's been, usually around 8.5)
Hardness: 6 (struggle to get this up to 8 or higher)
Temp: 25.8 Celsius
Calcium: 420ppm
Salinity: 1.020 (has been 1.021-1.025 the entire time since starting the tank) and just added more concentrated saltwater solution to the tank to start to raise the salinity slowly.

Any suggestions would be greatly appreciated. Thanks!

 

[keddre]

Are you finding the bodies, are or they just disappearing?

 

[nautical_nathaniel]

How big are they? The super tiny ones most LFS's push onto us don't last long at all in my experience. I get the one's that are a bit bigger, around the size that they need 3/8-1/2 inch or so hole in the shell they live in.

 

[awtank2017]

How big are they? The super tiny ones most LFS's push onto us don't last long at all in my experience. I get the one's that are a bit bigger, around the size that they need 3/8-1/2 inch or so hole in the shell they live in.

Thanks! I will look 1 or 2 bigger ones. Most of them were large, but not that big. Is that 1/2" horizontally or vertically? Also, most of them had oval shells rather than the round shells of turbo snails, but my LFS gave me mostly empty turbo snails shells so that I would have extra for them to grow into. Is that okay or should they have been the same style shell they were in?

 

[awtank2017]

Are you finding the bodies, are or they just disappearing?

Just disappearing, I just keep finding empty shells. I thought maybe the one that survived after the first round was eating or killing the others, but now I am not sure since I can't find any.

 

[Bouncingsoul39]

You need to raise your specific gravity to 1.025-1.026 and keep it there consistently. That is the reason they are dying. Inverts need NSW conditions and are sensitive to changes in it. Any inverts still alive at the SG are just plain lucky or very stressed and soon to die.

 

[awtank2017]

You need to raise your specific gravity to 1.025-1.026 and keep it there consistently. That is the reason they are dying. Inverts need NSW conditions and are sensitive to changes in it. Any inverts still alive at the SG are just plain lucky or very stressed and soon to die.

What do you mean NSW and SG? My snails and urchins show no signs of stress. I am working on raising salinity, but I don't want to raise it too quickly. I tested yesterday and it was 1.024 so I am not sure why it dropped so much over one day.

 

[nautical_nathaniel]

Thanks! I will look 1 or 2 bigger ones. Most of them were large, but not that big. Is that 1/2" horizontally or vertically? Also, most of them had oval shells rather than the round shells of turbo snails, but my LFS gave me mostly empty turbo snails shells so that I would have extra for them to grow into. Is that okay or should they have been the same style shell they were in?

I was using that measurement like an average diameter for the shell opening. The bigger dwarf zebra/orange and black hermits are hardier than the reg legged and blue legged hermits in my opinion too. Halloween hermits are cool too but require special shells and get much bigger.

 

[awtank2017]

I was using that measurement like an average diameter for the shell opening. The bigger dwarf zebra/orange and black hermits are hardier than the reg legged and blue legged hermits in my opinion too. Halloween hermits are cool too but require special shells and get much bigger.

Thanks for the suggestions on dwarf zebra/orange and black hermits. I think I had red and blue legged ones, maybe one zebra.

 

[nautical_nathaniel]

Here's what I was talking about so you can compare them to what your LFS has. My LFS gets random species in all the time and just sells them as "hermits" and you have to be choicey about what they grab in the tank for you sometimes.

http://www.liveaquaria.com/product/613/dwarf-zebra-orange-black-hermit-crab?pcatid=613&c=497+501+613

 

[awtank2017]

Here's what I was talking about so you can compare them to what your LFS has. My LFS gets random species in all the time and just sells them as "hermits" and you have to be choicey about what they grab in the tank for you sometimes.

http://www.liveaquaria.com/product/613/dwarf-zebra-orange-black-hermit-crab?pcatid=613&c=497+501+613

Thanks for the link. I tried IDing mine when they went in our tank, it's in my classroom. Most were the red or blue, one it was hard to tell because it wouldn't stay out long enough for me to see it's claws, I wouldn't either with a giant face looking at me

 

[Bouncingsoul39]

What do you mean NSW and SG? My snails and urchins show no signs of stress. I am working on raising salinity, but I don't want to raise it too quickly. I tested yesterday and it was 1.024 so I am not sure why it dropped so much over one day.

NSW= natural salt water SG= specific gravity. If you are now at 1.024 you are in range of acceptable. The lower level you mentioned before of 1.020 will kill inverts. Urchins and snails don't show signs of stress. It's not like a dog or cat that's going to whimper or hide if it's hurting. They will just drop dead.

 

[keddre]

If you are now at 1.024 you are in range of acceptable. The lower level you mentioned before of 1.020 will kill inverts. Urchins and snails don't show signs of stress. It's not like a dog or cat that's going to whimper or hide if it's hurting. They will just drop dead.

+1

Just disappearing

What's the rest of the stocking like? Do you have any crab eaters?

 

[awtank2017]

NSW= natural salt water SG= specific gravity. If you are now at 1.024 you are in range of acceptable. The lower level you mentioned before of 1.020 will kill inverts. Urchins and snails don't show signs of stress. It's not like a dog or cat that's going to whimper or hide if it's hurting. They will just drop dead.

The salinity has been at 1.023 for the past month and that's when I have been loosing them. Today was the first time it dropped to 1.020.

 

[awtank2017]

+1


What's the rest of the stocking like? Do you have any crab eaters?

I have 1 blue tuxedo urchin, one purple firefish and one tailspot blenny (added one week ago after first and part of second die off), 5 turban snails, and 1 tongan snail. Corals are hammer, duncan and kenya tree (look better than ever!)

 

[keddre]

The salinity has been at 1.023 for the past month and that's when I have been loosing them. Today was the first time it dropped to 1.020.

While I don't think your level should be deadly, NSW is around ~1.026, so I would keep raising it. Others may say different on if it's deadly or not.

I have 1 blue tuxedo urchin, one purple firefish and one tailspot blenny (added one week ago after first and part of second die off), 5 turban snails, and 1 tongan snail. Corals are hammer, duncan and kenya tree (look better than ever!)

No of those set off my radar. Are you dosing anything?

 

[nautical_nathaniel]

Check for gorilla crabs, mantis shrimp, and, yes even a hitchiker octupus. If you find a lot of empty shells in pile around a rock, you may have something catching and eating them.

 

[Bouncingsoul39]

The salinity has been at 1.023 for the past month and that's when I have been loosing them. Today was the first time it dropped to 1.020.

1.023 is still too low. How can water just drop to 1.020 in one day? In order for that to happen, fresh water will have had to be added.

 

[nautical_nathaniel]

1.023 is still too low. How can water just drop to 1.020 in one day? In order for that to happen, fresh water will have had to be added.

It can happen if you're using a hydrometer to read salinity. The one I had would fluctuate depending on how well it was cleaned the last time and I think temperature comes in to play when using them as well.

 

[awtank2017]

While I don't think your level should be deadly, NSW is around ~1.026, so I would keep raising it. Others may say different on if it's deadly or not.



No of those set off my radar. Are you dosing anything?

Not dosing anything.