Option 1: Heating the small room that the fishtank is in
OR
Option 2: Heating the fishtank with a underwater heater.
Iam thinking option 1 because with option two the heated water's heat would escape into the room.
OR
Option 2: Heating the fishtank with a underwater heater.
Iam thinking option 1 because with option two the heated water's heat would escape into the room.