I'll tell you what makes me cringe. It's people who compare fish to humans. I have a secret to share with you that nobody knows. Fish are not humans and don't care if they eat the same thing every day. Wow! What a revalation. Shhhhh, keep it quiet though, let everyone else keep thinking fish and humans are exactly the same.

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BUT, here's where you're wrong....I don't know about YOUR fish, who probably have the same bland food day after day, but ALL of my fish, even my lowly goldfish, have a decided food preferance. I have not one, but 2 brands of goldfish food. Plus different treats that are healthy for color and digestion. and I find that my fish eat much more heartily when I swtich randomly between foods. Also, when I supplement with freeze dried gammarus shrimp and freeze dried bloodworms. I find they like the gammarus much more. Plus it's roughage for their bellies, so it's good for them.
That's like saying the fish have no feelings. Which is still quite lame thinking.
Everything has tastebuds, everything likes a little variety now and then, and besides, if you only feed one brand, it may not have EVERYTHING your fish needs to be truly healthy and happy. And a happy fish, is a brilliantly colored specimen that will give you YEARS of enjoyment. And if fish are not truly sentient beings with different tastes, why do they have individual personalities? Or, do you not notice these subtle differences while you are feeding the same bland flake or pellet every single day?
I'm not flaming anybody, I'm stating a valid point. And as for which food is the best, I have only JUST gotten back into having cichlids again, the last of which were convicts in a community tank, and I was roughly 8 at the time, and don't remember what my sisters fed our fish....
Variety is a MUST though!!