Right. The dominance depends not only on size but also temperament and gender, so these may outweigh the size advantage, although I admit I am surprised the lighter colored one feeds more because I'd expect it to be more hesitant at the feedings and more skittish and hence feed less. Yet, overall your situation seems out of the norm, they are way too skittish for what'd be expected. Well, now that they are in the pond, let's see what happens.