i agree... i have mine on 76 but can tolerate up to 70. pimas would likes cold water. basically tropical weather. if you keep them inside the house they should be fine until winter comes where in you need a heater.
i would do it what do you have to lose. Get another one if it dies.70 isn't that cold. Just make sure that you drip him for a while to get him aclimated
ANY tropical fish can survive water temp from 62 degrees and over. As long as the change is not dramatic. I don't use heaters in my fishtanks ranging from 40 to 330 gallons ( I do not recommend this for everyone). My neighbor has a 700 gallon pond and I kept red devils, Syspilum, flowerhorn, and pacus in there til winter time. I noticed the problem when the water temp dropped to 55 degrees. They were just floating on their sides as if they are in a dazed.