Being very NEW to this hobby I probably shouldn't speak up yet. I got into it by getting a betta boy as a gift and then meaning well got him 2.5 gal "betta bow" filtered tank and petco guy advised platy and molly (1 of each) for companions.... Needless to say... That was BAD!!!! Well... While doing all of my research and while my bigger tank was getting ready for The Trio (as I call them) which took for about 3 months) I never had any major issues except for the initial intro of the other 2, betta boy started flaring and after few hrs of watching that put him in separate planted bowl while putting more live plants and rearranging hiding places in the tank. He was back in the very next day and it's been nothing but peaceful tank since. Plus amazingly with being so overstocked in this tank my ammonia never went above 0.5, and that was only 1 instance (did something stupid) and couple of other times at 0.25, other than that, perfect chemistry the whole time. Now this original betta boy and his 2 companions are in their bigger home with some young family fish for the platy and molly, and few ghost shrimp and couple of snails... He has yet to bother anyone, the mollies and platies either mind their own business or interschool with each other, and the Betta Boy (named Parker) is kinda of a Patriarch looking after his flock. It's very cool to watch. I should add that since that unfortunate beginning I grew my fish family by 4 more bettas (just love them!!!!) they each have their own filtered tank with lots of live plants, driftwood, places to hide... And for them... Their shrimp and snail companions were added once they'd had time to establish their territory... But they, too show no signs of aggression to their tankmates so far. I may try to introduce couple of fish at some point and see how it goes but for now, my Beginner's Theory is: if you have heavily planted tank (live plants), decent space for them, .... And don't starve them to death.., betta's don't have to be aggressive, neither one of mine (5 males) are. I feed mine twice a day, am is usually frozen peas or mini betta pellets, or betta flakes (went through few brands bfr found what they liked), evening is always frozen food (brine shrimp, blood worms, glassworms... Rotating them around... Still gotta look up the garlic recipes to try on them, so far everyone has been healthy and eating and growing but gotta be ready for those evil germs
long story, but figured if someone is asking about the betta... Chances are they are as green as I was 3 months ago and like me they want to do the right thing. Hope I was able to help, at least a little
enjoy your Betta, they are so full of personality and their beauty is unsurpassed