Adding a Dwarf Zebra Hermit Crab (Yay or Nay?)

[sweetsiren]

I'm considering getting one Hawaiian dwarf hermit crab for my half-gallon shrimp bowl. Supposedly, the crab and the shrimp are native to the same waters and the crab is unlikely to feed on or fight the shrimp.

Water Conditions for the crab
72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.023-1.025

I know the shrimp can live in water this temperature, but can I add a bit more salt (over the 1.005—1.016 sg range) or up the pH without harming them?

[sliphorn]

I'm considering getting one Hawaiian dwarf hermit crab for my half-gallon shrimp bowl. Supposedly, the crab and the shrimp are native to the same waters and the crab is unlikely to feed on or fight the shrimp.

Water Conditions for the crab
72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.023-1.025

I know the shrimp can live in water this temperature, but can I add a bit more salt (over the 1.005—1.016 sg range) or up the pH without harming them?

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That salinity is awfully high for the opae ula long term. I would not do it. Opae ula do best by themselves. Consider a separate half gallon bowl for the crab.
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[sweetsiren]

Other (more experienced aquarists) have said they have shrimps that coexist with nerite snails and/or dwarf hermit crabs. I got curious as to how they do it.

[sliphorn]

Other (more experienced aquarists) have said they have shrimps that coexist with nerite snails and/or dwarf hermit crabs. I got curious as to how they do it.

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Nerites are fine in the same salinity as opae ula. Snails, particularly the ones that Mustafa sells, are part of a well balanced opae ula tank. I still say no to the crab.
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[Mustafa]

The crab needs much more food over time than the shrimp. The shrimp don't do well when you overfeed the tank, especially a tiny one like yours. And if you feed the shrimp every two months or so, then your hermit crab won't do well and eventually die. That's why it is not a good idea to keep them together. The snails sold here are just as hardy with about the same food requirements as the shrimp. Nerites eat *much*, *much* more. And when a big nerite dies in a little tank you have a disaster in your hands as it will pollute the water with ammonia and most likely kill the shrimp. Nerites tend to die in crevices behind rocks and stay undiscovered for a while.