Chop, I think you're doing everything right, and your fish should do just fine ! Your 120 gallon tank is providing your young fish with 20 g's each, which is great. Feeding sinking pellets is good too, much better for goldfish than flake. You may want to add some fresh veggies every now and then, for variety. There's some good food ideas here on this forum. I make a gel food for mine, and give them a treat of thinly sliced cucumber, zucchini or lettuce to nibble on (I clip it on a veggie clip that suctions to the side of the glass)
But what I think is the absolute best thing for goldfish (or any fish, for that matter) is frequent water changes. I got in the habit early on, of changing out about 25-30 percent every third day. Some people may say that's not necessary.... but imho, it keeps the water chemistry consistently good. As you know, goldfish are big waste producers, and even the best filtration system is no match over fresh clean water.
So if you want to see your goldies thrive and grow, my advice is to change out the water on a regular basis, the more the better !
btw, can you post some pics of your goldies ? we'd all love to see them !
