Below is a picture of Brutus III, the third beta I've had in my classroom over the years.
Previously, I had a tank with filter, heater and light, which enabled me to keep guppies. My school district's new rules have eliminated the use of electronic equipment, except those purchased through the school and required for classroom instruction. That meant the end of the guppy-filled tank.
My newer room, after the school's remodeling, now has a skylight which enables light through the weekends. So I returned my old self contained tank to service and supplied it with a resident.
The students enjoy Brutus well enough as a distraction. Betas are not as messy as goldfish, and equally hardy, so he's an obvious choice. Plus, he seems happy enough in his tank. Far better than the little cup he was in until recently.