Here some info I have saved on my computer from a few various sources.
(not my reasearch - just from my saved files

)
Total nutrition in a 100 gram sample of a feeder goldfish
Protein = 18% or less (2.5 times less then quality pellets)
Lipids = 5.60 g
Vitamin B = 2.8 mg
Vitamin C = 1.60 mg
Saturated fat = 1.08 grams (5-6 times higher then shrimp, crayfish ,similar items or quality fish food)
thiaminase - HIGH- this is what blocks thiamin absorbtion/breakdown and leads to vitamin and mineral deficiencies.
Hoefully that helps with what your looking for
Theres a few USDA studies scattered around online as well as some AVMA (American Veterinary Medical Association) and AVMJ (American Veterinary Medical Journal - you need a paid subscription for there)