I thought that Bio Gold + made a difference, but now I'm not sure. I looked over the ingredients and I don't think that MSG (monosodium glutamate) as the 11th ingredient is very essential to fish nutrition. My fish seem colorful, grow fast enough and live for a long time with the varied diet of live, frozen and dry food mix along with frequent water changes that I give them.
The MSG is what makes the fish love the pellets. It enhances the flavor.
Hikari is like Chinese takeout.. while NLS is something out of Subway. Bad analogy but you get my point lol.