Originally Posted by ChoclateBetta
No one can deny a Betta in a 10 needs less cleaning than a Betta in a 5 chemicals do not build up as fast also more exercise do not deny the truth.
Bigger tank doesn't technically mean "more exercise" my fish in the 2.5 swims around just as much as the one in the 10g. It just happens he has a little less room to do it in.
Consider this, I can run around a quarter mile long track for an hour OR do little laps around a room in my house for the same amount of time. Technically I'm getting the same amount of exercise.
All a bigger tank means is more space to explore, which gives the betta something to do other than something potentially dangerous, like say tail biting. But for some all that space could be stressful (kind of like a person who is afraid of going outdoors).