Pretty easy fish. Some issues though with keeping good water quality, some people get lazy.
Whatever is easier. Feed less but you can do it a couple times a day. Hikari BioGold is a reliable staple food which doesn't break down quickly and cloud water or make ammonia spikes when used as it should be.
Frozen baby Brine Shrimp and other Blood Worms, Tubifex, etc. A little goes a small way. Maybe a fasting day thrown in once in a while. Try feeding a cooked pea. A little aqua clear filter is a wise investement, along with a liquid testing kit like API, online is cheapest price wise.
A couple low light plants, a Nerite snail or other type (wouldn't go with a Mystery snail unless you do a 10G (if they die and you doen't notice right away they can nuke your tank with ammonia) and if you go with the 10G maybe a couple. Bristlenose Plecos or other small size Pleco to keep the bottom clean.
For water changes if you like to do a couple changes a week being less per change or prefer a larger 1x per week water change.
I liked doing smaller ones. Using a big togo cup and get a couple of pitchers (kind that can stack into each other are awesome from the $ store - 2 (30oz /trenta starbucks for a 5G) cups of water out into the pitcher and store a pretreated gallon of water under the cabinet to add back in takes less than 5 minutes average 2x each week.
A couple times per month good vacuum of the substrate, the the opposite weeks rinse the filter pad to clean. 20 min per week or less. [1 month - 1st week vac, next week filter rinse, 3rd week vac, then 4th week filter]
If you over feed you could need to to do more.
At first you are testing frequently to make sure you have everything right and then after awhile, you get the hang of it and know what it takes to keep stable parameters.
I like the smaller Fluval vac because it is smaller and easier to fit around a nano sized tank.
Also sometimes a Betta will not allow a snail or a Pleco in its tank, but generally if there is hiding places and some DW you can do a BN Pleco.
