One of the best ways to stay safe from predators, for an animal, is to gang together with your buddies. There is safety in numbers. But if species want to make the best use of a food source, normally it is better to be alone. The more you have to share, the less you get.
Things are different for these herbivorous yellowtail surgeonfish in the Sea of Cortez. Here the best feeding areas are controlled by much smaller, but much more aggressive damselfish. A lone surgeonfish stands no chance of grazing here. However, when they get together with their friends they can grab a bite with their friends.
Andy Raynor Dover NH