Haha, that's the exact question that came to my head.
They actually make spirulina tablets and powder for humans now.
I even found a recipe for a spirulina smoothie:
1 cup apple juice
1/2 frozen banana
1/4 cup frozen blueberries
2 tsp. powder spirulina
Blend until smooth
Current fish (includes all 3 running tanks): Polypterids, severums (of which I raised from eggs), gouramis, plecos (gold spot ones & a gurupa), loaches (zebras, yoyos, & a kubotai), macculocchi spotted silver dollars, an African butterfly fish, & Ctenopomas (a leopard & an ansorgii)