Join Date: Dec 2011
Location: Washington, USA
Shimp have a pretty small bioload but I've never kept them in anything less than a 2 gal, and that was for QT. I know others have had successful shrimp only tanks at 2.5 gallons, but I'd be wary about putting them in with a fish in anything that small-- my bettas have killed them in both 5 and 10 gallon tanks, poor guys. Only time I succesfully kept a betta with shrimp was in a 29 gal community where the betta rarely went to the bottom.
If you want to see the really cool behavior, you need at least 8-10, I think. Otherwise they mostly just stick to themselves and hide more. They will start to interact with each other if you have enough, and it's fun to watch them chase each other around for food, etc.
I've had really good luck letting them clean up the bottom & supplementing with sinking algae wafers & occasionally blanched veggies. They go nuts for cucumbers and spinach but pretty much ignored peas and cabbage. The blanched veggies thing is pretty new to me, I've only been doing that the past couple of weeks in my crab tank so I'm still experimenting with it. Algae wafers have been an old stand-by though.