It's my understanding that applesnails need 2.5 gal per snail especially when they start to mature. There is tons of great info on the site applesnails.net...........They definately need a heater between 71 and 80. the low end they grow slower but lay fewer clutches. High end if you are trying to get fertile clutches. I've been told by brededers that they live longer and lower temps of 71 or 72. They need a high ph to prevent shell erosion.