Yea, you would have noticed an improvement when changing to a lower grain food.
The grains is what dos them in, just a clog into those fragile digestive systems they have.
Soaking the pellets is good too, I think it keeps gas out of the system.
Here's a ton of recipes that are completely grain free. The gel is a better thing to feed as well since it's already moist. Anything like calcium carbonate/clay/bacteria supplements is optional... As long as you get the multivitamin in there. Vitamin C is easy to do with a bit of orange as a snack before a water change (since it's messy).
I use baby food recipes.. I had a bad experience blending chard (do NOT put the stems in the blender or your blender may burst into a ton of smoke
) so these are much faster, and they make smaller amounts of food. Even these will last your basically FOREVER with a goldfish.
Oh, and don't forget to freeze it. Lol. I'll PM you those since they are actually on another forum...