Leave the small fish, they will grow to be bigger fish. Also if the fish you are catching are all 1-2 pounds that means the population of bass is probably growing. Just to make sure though, make sure there is enough baitfish in the pond for them to eat, to prevent a stunted population. You can get a minnow trap for like $10 on Amazon throw that out there and if you get a bunch of minnows you are fine. If you don't, stock the pond with minnows.