To me, as long as you're drinking a bottle of water with it I see no harm. You get hydrated from coffee. Of course you need to drink water in general, but the concept of drinking cups of water to balance out dehydration from coffee is just a myth.
Reptiles do not maintain their own body temperature within a narrow range like mammals and birds, so controlling their environmental temperature is critical for normal activity and good health. Reptiles are poikilothermic-which means that their body temperature alters with the surrounding environmental temperature.
Amphibians have smooth, slimy skin that is covered with mucus secretions. This keeps their skin moist and allows oxygen to pass into their bodies. Amphibians cannot drink water with their mouths. Water is absorbed through their skin.