Well I voted the 2-2.5 because that's the smallest I have other than the 1 gallons, which are for quarantine. I have tanks from 2-20 gallons for bettas. Why? Because unlike the belief that "the bigger the tank the more the work" bigger tanks are less work, and more beneficial to the fish in so many areas.
At first, I thought the poll was asking the size tank your betta is in. D'oh. *face palm*
I voted 5 gallon, since my betta is in a tank of that size. I think smaller tanks and bowls are fine, but I like to see them have a bit more space to swim around. Plus the bigger the tank, the more ornaments and plants you can put in there. So I'd say a 5 gallon, although the smaller tanks and bowls (2-3 gallons) can work fine too. =)
there wasn't an option for multiple tanks .. i have 9 boys in the house .. 7 that i take care of .. so i voted for 5g at least cus thats what i personally feel is a comfortable environment for my boys .. since in a 5g tank i take into account that .. after adding decor plants substrate heater thermometer etc etc .. and then add water .. it's more like 3.5 - 4g of actual water volume since all the stuff you put in there take up water volume in the tank .. also the 1 inch space for jumping prevention also reduces the actual water volume in the tank ..
i've tried with 2.5 .. and all the necessities .. and it just looks cramped in there and ended up with only 1.5g's of water volume after putting all the necessities in there .. and maintenance on a 2.5 is just a lot of work .. so i just bare bottom the 2.5 i have and use it as a QT tank for my chronic sbd boy
here are the tank setups in the house:
one is a filtered cycled 10g NPT with one boy betta 5 octos and 1 apple snail.. this tank pretty much takes care of itself .. my bf takes care of water changes on this tank since this is his .. about 1-2g change a week
1 boy in another filtered cycled 10g semi planted tank .. i do 3g's water changes a week on this tank since it's still new and not completely established yet
5 boys each in their own semi-planted 5g tanks that have been established for 9 ish months now .. so i do a rotating water change schedule of 25% a week 50% next week 25% 3rd week and 80% + decor rinse last week for the month
1 boy in a bare bottom 2.5 with a marimo ball and a betta log .. which gets 10% - 25% changes every day to get the film off the surface and waste is removed immediately .. i mean this literally .. since i work at home and i am in view of him all day except when i'm sleeping or out running errands ..
1 boy in a 1g .. which my bf does 30% water changes every other day with a turkey baster =D
My girl is in a 2 gal, and my little brothers is in a 1 gal, both unfiltered. But I do weekly water changes, and I try to keep the temps to at least 72 degrees. I can't have big tanks, because I have no filter and I am not strong enough to lift the tank to do water changes.
IMO-water quality is more important than tank size....Bettas can be neglected in a larger tank just as they can be in a smaller tank...it just may take longer....for some hobbyist they have a false sense of security in thinking larger tanks or even a filter will reduce the need for water changes.
IMO/E-each Betta is different in their tolerance to tank size as well-sometimes the long heavy fin males can have problems with too much space and/or with water movement-this can stress them and sometimes cause neurotic behaviors, health issues and fin damage....
Freshwater fish thrive with fresh water...to be a good keeper of fish you must first be a good keeper of water with the understanding of how they interact....