Question: do ghost shrimp need a heater?
Answer: If all you are keeping are ghost shrimp, you won't need a heater. I have read that they are more active in warmer water, though. Anywhere between 65-80F should be OK, with 72 being a great mid-point. ... If you use a heater, set it up a day or two before adding the shrimp to create a steady temp.