if u talking to me its about 4 mos..Other things can effect the difference a fish food can produce. How long have you tried feeding the NLS esclusively?
One piece of contructive criticism I would point out is that you didn't cite any sources or studies at all. At best this makes the article look like it's not very well researched and opinion based, at worst it points to possible plagiarism and blatant inaccuracies. Since you're a biologist and a vet tech and you've obviously had some college education, I assume you know this already. I don't think any of those things, but for future reference you should really cite...
My turn to take a stab! Hikari fails compared to NLS in many ways, but lets just talk about healthier ingredient choices. Hikari has MSG in their products.. NLS does not.