Fuge.
No skimmer does does all this:
convert ammonia, nitrates, phosphates, carbon dioxide to fish food.
remove carbon dioxide
add oxygen
bioaccumulate (filter out) toxins like copper.
stabilize operation and prevent tank crashes by consuming ammonia over nitrates.
Actually a skimmer does most of what you just listed.
convert ammonia, nitrates, phosphates, carbon dioxide to fish food... Doesn't create fish food, but removes these from your tank.
remove carbon dioxide... check
add oxygen... check
stabilize operation and prevent tank crashes... check

