Betta Tanks

First: 1/2 gallon is too small for a betta. I suggest getting a 2.5 or 3g aquarium for them.
You need filtration also.

3 times a day is probably too much for a betta. Switch it down to 1 or 2 feedings a day.
Your water change rate is good.

As for the bettas looking bored, you need a decoration/hiding place for them to play in. I have a turtle decoration and my fish love it. you can also get a clay flower pot and put it in there for a hiding place.

Let others tell you more cuz I gotta go. Brother's turn. URRG!

First off, a half gallon tank is way too small for a pair of bettas. I wouldn't settle for anything less than a 2 gallon for 1 betta. People may stick them in little cups, but it doesn't mean they don't enjoy larger space. I have a betta in a 12 gallon tank and he likes to swim all over the place.

Secondly, do not keep a male and female together unless you're mating them (and then you'd need to remove the female) or you have a large tank. When it comes time to mate, if the female is not ready the male will harass her and one or the other will die from the result. The male will also attack the female after they mate as he defends his bubblenest.

Third, you don't need to feed them 3 times a day. A couple of pellets once a day is enough.

Finally, aeration is not necessary but will not harm them. If the aeration is causing alot of surface agitation, then that may bother them.

Why not get a 10 gallon??? I just bought one from petco for $6. Then get a divider and you can keep both in there. You'll need to get a heater and a filter.

Regarding filtration, bettas do need clean water so unless you plan on doing water changes everyday, some sort of filter is required (and we're not talking about the aerating unit).

Regarding mating, its a fairly involved process. Try doing a search in google on mating bettas.

The tank divider is a great idea. If you can't find a cheap 10 gallon tank, see if you can't find anything smaller like a 5 or 6 gallon tank with a divider. That way, you will only need one filter and heater.

ditto. as far as the filter and heater, it might be least expensive to get an aquaclear mini filter, via aqua preset 50 watt heater, and test kits to monitor your cycle, although that's not necesary if you just do daily 1 gallon water changes.

the total for the filter, heater, and an ammonia test kit is $21.97 at bigalsonline.com and you can take $1.99 off of that if you forgo the ammonia test kit. to get a nitrite test kit add another $4.97.

Then just get a 5 or 10 gallon tank and divider locally and you have an awesome betta setup

good luck