Fish: Fair Friends or Mean Moochers?
by Cristian Cruz, age 11
Sea creatures often form partnerships; while these relationships are sometimes mutually beneficial, other times they are not.
One partnership formed by sea creatures is between small, defenseless species and larger, more powerful species. Larger fish offer protection to smaller creatures. For example, the sea anemone serves as a defender of shrimps, small crabs, and juvenile fish. These smaller species are able to swim between the anemone’s lethal, stinging tentacles, which prevents larger fish from preying on them. In exchange for this service, the smaller fish maintain the cleanliness of the anemones by removing debris from inside and around them.
An additional partnership formed by sea creatures is between coral reefs, small fish, and parasites. The surface of coral reef fish is frequently covered by small skin parasites. Eating these parasites, small fish both fulfill their nutritional needs and help coral reefs maintain their health.
In contrast, some partnerships between species of the sea are only beneficial for one of the partners. Remora, a type of small fish, grip onto larger creatures like sharks, turtles, and whales in order to travel long distances, for example. However, sharks, turtles, and whales gain no benefits from this relationship.
It is amazing how aquatic animals can help each other to survive, even without knowing it!
DK Guide To The Oceans