I run my own business, out of a shared studio space in an old industrial building. In theory I do have studio mates, but they're there only rarely and I'm there all day every day by myself and get sort of desperate for company. So I've been thinking that maybe I could keep a betta there. My space is pretty tight, but I think I could squeeze in a five gallon tank, although that's the limit. If I do this, it will have a filter and a heater and plenty of live plants.

But there are two potential problems with trying to keep a fish there. The first is that several times a year I'm out of the studio for a week or two at a time; during some of those times, my studio mates are around enough that our plants still get watered occasionally, but a few times they've been in fairly rough shape when I got back. So I would need a reliable automated feeder at the very least, because the tank would have to be left alone for two weeks. Theoretically, there are dozens of other artists/artisans/etc who maintain studios in the building, but lots of them are around sporadically and the times of year when I am away are times when everyone else is away, too. So I would not want to count on finding someone to come in and feed the fish.

Which brings me to the other possible issue: the building is often a ghost town during July and August, because I'm on the top floor and it isn't air conditioned and it gets pretty warm. I make regular trips to the bathroom to run my head under the cold faucet; people who do come in tend to work in their underwear; etc. I didn't think to bring a thermometer in, so I'm not sure exactly how warm it is. It's what Boston people would consider warm, not necessarily what Florida people would consider warm, but I'm sure it's at least in the high 80's or maybe 90 some of the time, and the temperature doesn't really drop much at night. It's a big, solidly built old factory building and there is still a factory in part of it. So there's a lot of thermal mass, and once it heats up it stays hot until the weather is consistently cooler for a bunch of days in a row. For what it's worth, the place mostly doesn't get that chilly in the winter because the heat comes on full blast, and like I said, I'm on the top floor.

So the two questions:
Can a betta survive summer temperatures between 85 and 90? Are the automatic feeders reliable enough to leave for two weeks? (I know water changes have to happen too, but I'm thinking that should be OK if I do it before I leave and again when I get back)
If not, is there another fish you'd recommend that will be happy in a five gallon aquarium that potentially gets to those temperatures? Or is there such a thing as an aquarium cooler??

I even thought about sea monkeys, but I'd like to have plants in it and I don't know anything about what plants can grow in brackish water.