Aquatic Biomes — Marine & Freshwater

One day Nemo the clownfish is swimming through the ocean when the sun shines really bright through the ocean. Because of the sunlight, Bruce the shark is suddenly able to spot Nemo and tries to eat him! Nemo quickly escapes to the nearest sea anemone for protection. Which of the following would not be considered a biotic factor in this situation? (Hint: a sea anemone is considered an animal.)