I special mail ordered sera....the plecos didn't touch it. I bought Hikari, and the plecos and cories and otos love it. Then I tried Wardleys when I learned the first ingredient was spirulina......and when I turned the lights on the tank in the morning.....Wardleys were still sitting there! I tried to tell them Wardley's had more veggies which was good for them...but they wouldn't listen:headshake2:. I kept trying, they kept ignoring them. But mine are fine on the Hikari, they get plenty of algae and veggies otherwise. And I do not put them in the tank every day. At most, 3X a week. I do like Wardley's shrimp pellets for the cories, and the plecos always come right out on suck on those pellets too! And instead of breaking the discs in half for an oto, just take a tiny piece off, half is way too much. Less food polluting the water for even short periods of time if definitely a good thing for water quality.