Why do some fishes form schools while larger predators often hunt alone?

The primary reason many smaller fishes form schools is to enhance individual safety through collective defense. By swimming in large, coordinated groups, these fish can confuse predators; for instance, when threatened, schools may contract into tight, writhing spheres that prevent a predator from isolating and capturing a single individual. Additionally, schooling facilitates feeding movements and simplifies the process of finding mates.12

In contrast, many larger predatory fishes often hunt alone, utilizing a strategy of lying in wait to dart suddenly at their prey. This solitary, ambush-style locomotion is highly effective for predators but would be impractical for smaller, schooling species that rely on group cohesion.3

It is important to note that these behaviors are not universal rules. While many predators are solitary, some pelagic predators, such as tunas, also exhibit schooling behavior. Ultimately, these behavioral patterns are specialized adaptations evolved to optimize survival, feeding, and reproduction within their respective ecological niches.32