Greetings and welcome to the board!
Crackers probably fall under bread/carbos, which really aren't
the best for goldies. They have problems breaking down the
carbs. Aside from flake food(which should be soaked before
feeding) and sinking pellets, here's a list of stuff you can try to
feed your kids.
Lettuce (darkleaf), spinach, cucumber, zucchini, oranges, apples, grapes,
bananas, watermelon, pineapple, tangerines, peas, dehydrated seaweed,
shrimp, krill, bloodworms, earthworms(put in paper towel for 2 days
to purge the dirt out of their system). Plus they may like some
other things you'd never think of.