Hi tony, the current is one issue, but in case no one pointed it out before, you are a bit overcrowded in a 20 gallon tank.

After adding the otoes, your fish would thrive better if you had them in at least a 40 gallon tank.
Do you have any particular reason for having two powerheads in a freshwater tank? I have never done that myself, I do have one on a 55 gallon tank that has otoes, and a HOB filter, everyone in that tank seem happy. Otoes can be easily stressed, by the current or overcrowding, either way they may not thrive.