i own 3 as (of now), not counting all the countless 1-2.5 gal US betta tanks i have. they are 2 10 gal US and a 55 gal US. it all started with getting 1 male betta and keeping it in a little bowel and now i keep them in much larger and got more tanks. after my 55 gal is set and "fully" stocked (to what i like). i plan on getting a 150 gal and possibly setting it up as a mangrove tank for mudskippers and archer fish. i think that will be a cool idea. or use the 55 gal for the mangrove (though i think it will be too small) and use the 150 for my 55 gal fish and then some.