Freshwater shrimp question - sorry!

[mothrica]

Hi, folks.

I'm new to this whole fish thing, so pardon the ignorant rookie question.

I've got a couple of japonica shrimp in a freshwater tank and I haven't seen one of them in a couple days. Do they hide like this when they molt, or should I call for a coroner?

Thanks...

 

[LeslieH]

Yes, crustaceans hide because after molting the exoskeleton is soft which makes them easy prey for predators. The shells will harden within a few days and they'll be out again.

 

[mothrica]

Thanks. Speaking of which... I've read a few comments that even in a freshwater tank, you should be a little concerned about Ca levels especially if you use soft water, if you've got crusties. I've got shrimp and I use tap water from a water softener. Would they do better if I used hard tap water instead? Or are they able to pull out the tiny trace concentrations of cations in soft water or to 'eat' it from chewing on shells?

 

[mothrica]

Also, do they eat their old exoskeletons, or just discard them?