The Food Chain

As many of you know the food chain is divided by Producers and Consumers. Now CPs are plants thus they produce O2 so they are considered producers. However, they also eat prey. Which means they are consumers. So my question is where would they be placed on the food chain? Also would CPs be the only things that would go in this gray area?

Thanks in advance for any replies.

no cp would not be the only things in that area. Uhh
many seacretures have symboytic alge in them (like coral, some jelyfish, and lots others) that provide food for them, as well as the fact that the alge gets a safe refuge from predetors.