These are a bit pricey, but available at many chain petstores. I used Tetra Spirulina flakes before but these are quite superior. For starters, the pieces of kelp/algae are visible, and the texture is different; more flexible and “chewy”. Fish have to actually work at eating them, but REALLY enjoy them.
This isn’t suprising; Omega uses many fresh ingredients in their foods, which makes them superior taste-wise and nutritionally. There’s some good stuff in these flakes, and they’re a great choice for plant-eating fish.