Hi, and grats on the betta he's beautiful
I have a few suggestiond that you may find helpful and I truely understand the no pets allowed so you need to have a small aquarium no problem. If you plan on upgrading and want a small aquarium to hide, walmart sells a little cube aquarium it comes with air pump whisper filter light for like 16bucks it 1.5gallons. They also sell like 2.5g hawkeyes which are pretty small aswell.
I would recommend investing in a nice water conditioner and I use a hydor mini heater pad in my females 1.5 gallon (yes i got anotherone lol) i have 10g being setup eventaully for her. Anyways the heater keeps the temp stable between like 76-80 for me anyways it was like... 8-11 bucks I forget