* "Cold" is a broad term: There are many species of cold marine fish, each with different social behaviors.
* Pack behavior varies: Some cold marine fish are solitary, while others form schools or shoals.
* Factors influencing behavior: Temperature, food availability, predator pressure, and even the fish's life stage can influence whether they form groups.
Examples:
* Cod: This cold-water fish forms schools when young, but becomes more solitary as they mature.
* Salmon: While they migrate in groups, they also form schools during specific stages of their life.
* Squid: Many squid species form schools for protection and to coordinate hunting.
* Polar Cod: A fish that lives in very cold water, they are often seen in groups, but they are not considered "pack" animals in the traditional sense.
In summary: While some cold marine fish do swim in packs, it's not a universal behavior. There are many factors that influence social behavior in fish, and "cold" is just one element.