It may have been my post you read, about my new gold nugget - GNs need a fairly meaty diet, and mine goes nutso for frozen blood worms and brine shrimp. Now that he's discovered Hikari algae wafers aren't going to jump out and bite him he'll eat those as well, but not with the same enthusiasm.
Commons are fairly vegetarian TMK, so make sure he gets his veggies to avoid constipation, but there's nothing wrong with meaty meals here and there. I'm sure in the wild they have quite a bit of variety in their diet.