I'm not sure on the exact percentages of fat, fiber, etc., but here are the ingredients in pro-gold: "Krill meal, fish meal, shrimp meal, wheat flour, alfalfa, spirulina, immunostimulant, fish oil, and much more. Plus all the vitamins and minerals to maintain healthy goldfish. 40% protein." The only filler is wheat flur and that is just to hold the pellets together.
The other bag of food I have is Hikari Gold, which isn't as good, but still better than cheap flakes. The nutritional analysis is: 35% protein, 7.4% oil, 1.8% fiber, 8.3% ash, and 1.2% phosphorus. Vitamin A: 19,000 IU/kg, vitamin C: 60 mg/kg, vitamin D3: 3,900 IU/kg, and vitamin E: 550 mg/kg. Doesn't say for calcium, iron, etc., though I see those in the ingredients list.
I'd be interested to see the analysis of some other popular foods as well. Does anyone know the info on pro-gold? What about Omega One?
By the way, in my opinion, you generally get what you pay for. I wouldn't be able to survive on ramen noodles day in and day out for my whole life, so I don't expect my pets to eat junk either. My goldies eat pro-gold and homemade gel food and I can see the difference in them since I stopped feeding only the Hikari. They have grown, their colors are brighter, they are shiny and active. Most of all, they BEG for food and began eating out of my hand. I take all these signs to mean that they like the better stuff, so that's what they get. I still feed other things, but not as their staple, and usually only to mix into the gel food I make.
A side note: the number one thing to think about before you get a pet is "can I afford it?" They are not cheap. I have many times spent my last twenty dollars on my cats' Science Diet and eaten the ramen noodles until payday. They don't choose us and they deserve the best we can give them, or we shouldn't have them in the first place. Just my opinion. Back to the question at hand