my crystal red shrimp were swimming crazily around the tank, strange behavior like trying to escape from the tank, swimming top of the water, hanging around the HOB filter outlet and they lost their front legs too. i have tested the water, it seems fine. and i did water change by 25% twice. but still acting weird. does any1 have the same problems like mine before ? plz share with me, so i can help my shrimp out.