Personally, I almost always regret getting the smaller tank. Our 75g is great, but a 125 would have gone in that spot. and the fish selection would have been larger. Ultimately it depends on what you really want to keep. Schooling fish can go in every size tank. But severum (i want some) and orandas (I also want some) can't. So, If you want the big fish, you'll always regret not going bigger