I helped set one of these up a a few months ago. Heater cords apparently are racetracks for shrimp as they love to climb out and explore. The afore mentioned shrimp met their demise during a replant. It seems that the mulb stirred up was toxic and the shrimp first 'went crazy' and the 'dropped dead.' That said, having a no heat/light/filter bowl is possible, but fairly tricky.