My betta got stuck in something like this. I thought he wouldn't be able to fit...apparently, half of him could. Just be careful and measure all the in and out openings. Block all of the openings that might be iffy. the Hydro Theo Heater SO FAR hasn't gone haywire on me yet, and I do suggest it. Good luck!
i looked it over, and the only opening that's iffy is that little upper-level window. i've gotta wait till Jack arrives to be sure of his size, but other than that, the openings are nice and big with smooth, non-dangerous edges.
I managed to get a heater, filter, gravel, 7 silk plants, a betta leaf, a marimo, and all the water quality chemicals & tests, epsom & aquarium salts, and food for my 10g tank for $30 shy of $200.
You should be able to get away with just the food, water conditioners, deco and tank for way cheaper than $200 but I wanted to make sure I wouldn't have to run out in the middle of the night to Walmart to get much needed medicines.
Live plants are more ideal than silk plants as they help keep the water clean which means a bit less water changing, so as this would be an office pet, I'd recommend live plants.
14 gallon tank at petco, came with filter,heater,fish net,tub of flakes and water conditioner and thermometer - 70 dollars
you can get the same kit in 10 gallon for 50 - 60 dollars. the filter is an aqueon quiet flo filter, it seems fine for bettas,
got a bag of black gravel for 15 bucks. u can prob get cheap snad for about 5 bucks some place.
1 piece of dritwood - 4 bucks
2 live plants 6 bucks.
a pack of fake plants with 3 in it - 10 bucks
tub if betta flakes - 4 bucks
betta fish - 3 bucks
a japanese style hut ornament 10 bucks
so all in for a ten gallon with some real driftwood and a couple live plants and a hut of some sort for hiding and your fish and food and all that stuff your lookin at maybe 90 - 110 bucks all together and your tank will look great