It's a good idea to have one. If the temp gets below about 70 degrees it's really too cold for them. They like to be much warmer, like the upper 70's, but if the room you have him in is normally warm, it shouldn't be a problem.
Sure. BTW, does the water feel watm or not? Because in the tanks with no heaters, the thermometer tells me its fine but it feels a lil cold. Mmm, methinks I'll get an electric one...
when the water feels warm its like 90F so yea it should feel cold! cause like bathwater... warm bathwater is like 200F and will kill a fish in a second! its kinda weird but yea!
Okay, let's try again. It really depends on how cool your home is. If it is not very cold then you should be okay. Some of the breeders on this forum don't reccomend heaters because they feel like a little temperature variation is good for the fish and will make them hardier. I have two bettas in my office at work and do not use a heater in their tanks because they stay above 70 degrees all the time. I do use one in the betta tank in my bedroom at home because my hubby likes it cool in there and the tank was dropping down into the 60's without a heater.