My red and white ryukin "Trinket" has suddenly started having swim bladder problems when I feed him his pellet food.

I was using Bio-blend. I tried soaking it in water with no luck. :angry: He still bobs around like a cork. I had to feed him peas just to get him back to normal. I bought some flake food for him (Nutrafin Max spirulina flakes) and he seems to be doing fine with that. I can't keep feeding him just the spirulina flakes so I was wondering if anyone could recommend a really good flake food. Thanks! :goldfish