Originally Posted by BBradbury
Corydoras aren't schooling fish, like Tetras. Corydoras are shoaling fish. There's a difference.
Andy Sager: Most, if not all, species of Cory cats "school" and do best when kept in multiples in an aquarium. You won't see the schooling behavior of a Tetra in cories but you will see them together more than apart.
The main difference is that in Tetras and other schooling species, they generally school for protection. Cories don't need the school for protection but more for company ( for a lack of a better word.) In the wild, these fish are rarely seen not amongst a larger group of similar fish. In an aquarium, they just seem to do better when not kept alone. ( I used the " " around school because I couldn't come up with the word Shoal before my morning coffee. Thanks BB