I bought some ghost shrimp a while ago, put them in my unheated tank, and they were dead by the next morning - I was told that the summer temp swing from 74 to 80 degrees was too much for them. Haven't bought any more because I have mainly hard water tanks for the guppies, and decided otos were easier on the wallet and to keep, in my soft water 80 gal, kind regards, Susi Barber