Why do fish need to eat other organisms ?

Hello There!!

Explanation:

They are important as food, shelter and also produce oxygen as a byproduct of photosynthesis, which fish and other aquatic organisms need to breathe underwater. The next step includes the zooplankton and aquatic insects. ... Some aquatic insects also eat algae, while some are predators and eat other insects or zooplankton.

hope this helps,have a great day!!

~Pinky~

they vary. it used to be meat, grain, bread, candy, beverages, donuts, and fruits/vegetables. now they added exercise in.