Start offering them some cooked veggies every day. Cooked, plain broccoli florets are a great, easy one. Spinach, peas, cauliflower & zucchini are other good staples. Pretty much any plain, cooked veggie can be fed as long as its mashed in bits or soft enough to tear. Avoid heavy starches (potatoes, corn) and anything spicy (onions, hot peppers). Make sure you remove the shells on peas. Remove anything uneaten after 24hrs & replace. This will also help with swim bladder issues related to diet. Make sure you are only offering small meals of pellets- goldfish do not have 'true' stomachs & will gorge themselves if given the opportunity. Its better to offer a few small meals over the course of a day & have veggies available for grazing. Just my opinion, but presoaking a sinking pellet really isnt necessary- you will lose alot of the nutritional value by doing this. I would just offer them smaller, more frequent meals & daily veggies.