as i sed b4, i divided my 4gallon(imperial) in half, and even then it looked way too cramped, and i struggled to filter something so small, coz all i cud get in there was a sponge filter, so one side if the divide never had any water movement, and the stats were always all over the show
so id like to know how u filter ur 2.5 gallon and heat it. oh and maintain the water stats, coz i sure as hell cudnt do it in my 4gallon, and i lost a betta as a result
maybe u shud get a bit of experience 1st, learn a bit about bettas b4 u go giving out advice
and no im not being mean, im just sayin what alot of people r thinking