Beautiful fish!
Congrats!

Do you have a water test kit?
Is your tank cycled?

I don't keep any fish I have to heat, but I've kept two common gold fish in a 50gal water trough in our greenhouse for several years. They are relaxing to watch. I break a lot of rules with them: no electricity in there, so, no air stone, nor filter. I keep the water healthy with drip jugs from above, daily siphoning of waste off the floor, and big water changes. Obviously, bettas are different, esp. with O2 levels lower in warm water, and far less air surface area in an aquarium (much less one can get away with).

Planning for shubunkin goldfish in our 350gal stock tank this spring.

Keep an eye on water chemistry (ammonia, nitrites, nitrates - etc.) until you know the tank is cycled. KGTropicals is a video channel that gives good basic fish care, although their business is African ciclids (spell?).