Ammonia and FW crabs

[Buckeye_ME]

My ammonia has been high lately, I think a bit due to overcrowding. I'm working on a bigger aquarium, but want another way to fix it quickly.

Would a FW crab help with the ammonia? Any specific recommendations?

I'm in the central Ohio area and the only thing I've found at LFS are crayfish.

 

[Veneer]

Probably not - many freshwater crustaceans tend to be sensitive to degraded water conditions. A crab, while it might consume some excess food and decaying organics, ultimately entails an increase in bioload (not necessarily sizable in and of itself, but significant in the context of a typically "messy" nature). Most crabs marketed for freshwater aquaria are, in truth, neither freshwater (many do best in water of brackish salinity) nor fully aquatic. Of the few truly suitable species available (as the likely Gecarcinid "Indian rusty crab"), most will shred plants and consume fish.

Can you describe your present setup?