Have a read through the ingredients of that food with the spirulina label. When I did that I was quite surprised. The spirulina flake that I bought, a brownish green colored flake has fish sourced protein as the first ingredient, then has 4 other components listed ahead of the algaes. Right after the spirulina algae, the next ingredient is back to shrimp meal and dried plankton. The only thing that is spirulina about my spirulina flake is that there is a little spirulina in it. It is basically a high protein, 45%, high fat food that has added vitamins in it. I am treating it more as a staple diet than I expected to when I ordered it.

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Fishless cycling