is a heater or pump acting up? sometimes (not too often) they can have faults and release stray currents of electricity in the water. water params as well.
0 ammonia 0 nitrite 5 nitrate
I did add some water last night, mostly to top off evaporation.
Neither the pump nor heater seem to be having issues.
The loaches themselves aren't paled out or red-gilled or any of the usual indicators of stress.