For the one you commonly find in pet stores, it's a fancy variety of Betta splendens. The wild B.splendens is green/red and has short fins. There are about two dozen, maybe more to be discovered, other species of Betta also. Such as B.imbellis and B.smaragdina.

yes what about the betta fish and mirror?? will it flare or just ignore it?please give details

Betta fish need filtered and oxygenated tanks just like other freshwater fish. Pet stores that tell you that Betta fish don't need much room or filtered tanks are either ill-informed or just plain unethical. Too much current flow isn't healthy since Bettas like slow moving water. If you are putting a plant inside a tank with your Betta (and not keeping the Betta in a vase with a plant growing out of the top and the roots growing into the Betta's space), any freshwater fish-friendly plant is good. Just make sure that it is soft so it doesn't damage the Betta's delicate and beautiful fins. Don't put a Betta in a vase with or without a plant growing above it. Also, don't keep them in tight containers or small cups. This practice is cruel and inhumane!

Yes because they are a living thing.

i have had this happen lots of times whether your feeding them or not... it scares me every time... and it is with different betta fish so i think it is normal!