Why Do Fish Shoal?
Most shops will try and sell you small fish in groups instead of singles. Although this is a good way to sell more fish, its real purpose is to make sure the fish are kept as they should be - in shoals. Take a journey into the fishes mind to find out why
How fish work in shoalsMany fish shoal or form schools in nature, and the reasons why they do this have effects that can be seen in the aquarium. The difference between a school and a shoal is subtle; A school of fish is a tightly regimented formation where fish swim an equal distance apart and the group turns as a whole. A shoal is a less formal arrangement where fish swim close together and follow the same general direction but each fish may do as it pleases.
Virtually all grouping freshwater fish found in the hobby are shoaling fish rather than schooling and should be referred to as such. Natural shoals can range from groups of tens to hundreds (Such as Corydoras), hundreds to thousands (such as Neon's & Piranha's) and in the case of some open water marine fish, in millions. Knowing why your fish shoal will help you to understand their behaviour in the aquarium and in some cases, help to eliminate potential bullies and compatibility problems.