There are habitual swarm fish that swim together all their lives, but there are also opportunist swarm fish which only pull together during an attack, or in times of danger.
Sumar tegundir synda saman í torfum alla sína ævi en sumir eru tækifærissinnađri og sækja ađeins saman ūegar árás er gerđ eđa hætta steđjar ađ.