On the (off) topic of spirulina flakes, the most veggie heavy flake I've seen is here:
http://stores.intuitwebsites.com/Aquarisms/-strse-31/Spirulina-Plus-(1-fdsh-4lb)/Detail.bok
Ingredients: Spirulina, Soy Flour, Pea Powder, Alfalfa Leaf Powder, Wheat Flour, Wheat Starch, Carrot Powder, Spinach Powder, Fish Meal, Fish Oil, Wheat Germ, Brewers Yeast, Kelp Powder, Zucchini Powder, Kale Powder, Beet Powder, Soybean Oil, Lecithin, Wheat Gluten, Astaxanthin, Natural Mixed Tocopherols, Rosemary Extract, vitamin and mineral supplements.
There's no breakdown of protein, fat, ash listed but looking at the ingredient list it's extremely heavy in veggies and from using the flake, very little is used for binding (it crumbles pretty easily). If your fish aren't used to veggies they may snub it at first. I almost always have zucchini or squash in my tanks and my fish took to it right away. My brother had to train his tropheus onto it (they weren't used to a ton of veggies) but now they eat it like pigs.