SPSHolic's temp blogger: Schooling and Shoaling in fish behavior

Many people ask in RC forum about schooling fish like " I'd like to have a school in it in my tank,
What's a good schooling fish? " and many people answered anthias, green chromis, cardinalsdo. but Some people say that these fishes are not schooling but shoaling!!I think I need to summarize the term schooling and shoaling.

Here is definition of schooling and shoaling

1. School. A group of fish that swim in a
synchronised manner, i.e. with similar speeds and direction. They also display a
consistent Nearest Neighbour Distance (NND), which means they maintain the same
distance between all immediately adjacent fish.
2. Shoal. Fish which are randomly
orientated within a group and exhibit a variable NND. Shoals of fish on the move
nearly always form schools.
http://www.thatfishshop.com/reference/shoal.htm

clown fish do not school or shoal. In the wild they will group with a male and female sexually differentiated pair and 3 to 6 sexually undifferentiated individuals around an anemone. By the way, this is called association; the anemone hosts clown fish, the clown fish associate with the anemone.

This is snorvich(Steve)'s comment (http://www.reefcentral.com/forums/showthread.php?s=&postid=12057421#post12057421)

Some butterfly fish will also shoal although none will school. Some of the fish that I have seen school are: barracuda, jacks, silver sides but schooling behavior in normal aquaria is not going to happen for a variety of reasons. Some of the fish I have seen shoal in an aquarium are some varieties of cardinal fish, yellow zoster butterfly, and some chromis and some anthias. I have heard that some tangs will shoal but have no personal experience observing this in aquaria. I have seen this in the wild many times but it depends on the species.

Pigmy Sweepers at the Georgia Aquarium. And They are now schooling~!(http://i142.photobucket.com/albums/r118/untamed_photos/Aquarium%20Construction/100_0024.jpg)