Hi i'm new to this site, but I love it already!

I have three Bettas (all males) two are a 2.5 gal tank with a divider. And one is alone in another tank.
The thing is the divider is see through and they can see each other (i was worried about this at the store but my sister told me it she thought it would be okay). One is bigger than the other and intimidates the smaller one, flares it's fins wide, and the smaller one shrinks back and stares at like in fear. I feel so bad. will they get used to eachother? i don't want it stressful for them Specially since i love animals and want them comfortable, healthy, and happy.
Also i see that here some bettas respond to their owners. Mine don't respond to me. Am i a bad mama??? <img src="/images/graemlins/frown.gif" alt="" /> <img src="/images/graemlins/frown.gif" alt="" /> <img src="/images/graemlins/frown.gif" alt="" /> I just got them yesterday. I now have a thermomiter so i feel so much on nerve about the water being too cold. I have pellets and flakes no worms though.

I'm a little scared that they'll get sick cuz i'm not doing something correctly! ack *sigh*

Also they stay near the top mostly...i know they have to breath air but why do they stay there so much? are they bored? I'm planning on getting little toys for them. For now all i have is a plant on one side and pebbles. I want something for them to swim in and out of. are little statues good too?

P.S.
I got two bettas from a petco then today i got another (very long story) from a different petco from a different town. It seems the betta from the second petco is more healthy...his colors are gorgeous, his is so fiesty, he's bigger but not in a fat or bad way, and his fins are healthy.
The other two are smaller and their coloring isn't as vibrant. should i be worried???

Any advice would be so helpful!
Thanks!!