Okay, here we go.
You can't just use tap water for your fish, the chlorine will kill him/her. Use a dechlorinator like this one:
Some people use aquarium salt in their tanks, but it's not required. I do because it helps fight some deseases, reducess stress, and keeps your fish healthier overall. I use this kind:
No special filters are needed, but I would run mine a little longer if I were you. I leave mine on all the time except for on the nights when I have trouble sleeping. The waterfall filters (like mine) get really noisy if the water level get's low.
A heater is only necissary if your house is kept at a cool temperature. If you don't have a thermometer, get one. You can get little stick on one's for $1 at Wal-mart. You can tell if your house is kept too cool if the water temperature ever get's below 74 degrees. If needed, you should get one of those small 2-5 gallon heaters from Wal-mart. They are cheap and adjust their own temperature. They work good if you arn't breeding your bettas.
You'll never have to change the rocks in the aquarium, but you do need to clean them with a syphon every once in a while(about once a week for best results). In fact, if your tank get's really dirty, you might need to do a 100% water change and rince of the rocks. That shouldn't be necissary very often if you maintain your tank well, though. I really hope this helps you out! If you have any more questions, feel free to message me!
