To heat or not to heat?

[Orokahs]

So my friend recently got a 5.5 gallon tank. I helped her get it set up with 2 plants, anubias nana and java fern. Theres also a plastic coral thing and petco sea blue gravel. We got a glo light and an in tank filter, for 3 gallon tanks, because she's getting a betta. We're going to pick up the fish tomorrow and I have a few questions.
First, do we need a heater? We want to get a betta, a few ghost shrimp and a cory or something. We'll also try to get a few more plants, but we're not sure which type yet. Second, what fish would work as tankmates? And third, we got a bottle of betta water dechlorinator, but we still need another bottle. Is it okay to get another bottle with the fish, add it, and while they're acclimating to the temperature, let it settle?

 

[cmwalters]

Bettas are a tropical fish and prefer their water around 80 degrees. So yes, I would get a heater. A 25 or 50 watt heater would suffice for a 5.5 gallon. What do you mean by betta water dechlorinator and that you need another bottle of it? If you just mean water conditioner I, and a lot of members, suggest Seachem Prime. Also, the betta will most likely be fine with the ghost shrimp, but corydoras are shoaling fish and need to be kept in groups. Pretty much every species of corydoras is much to big for a tank that size, so I would just stick to the betta and shrimp.

 

[Orokahs]

What other small single or pair fish could I use? A rasbora or two?

 

[Rivercats]

A 5.5 gallon tank is too small except for the one betta. You can add a ghost shrimp but it will depend on the temperament of the betta as to whether it will go after the shrimp or not.

 

[cmwalters]

With a betta, then there is not much else you can do with the tank. Besides the ghost shrimp.