Tightest schooling fish

Rummynose tetras are pretty much universally recognized as the tightest schooling fish out there.


However, how big is the tank? Fish school as a defense mechanism against predators. They like to be close to each other, so that each member of the school can see all the other members. In that way, they have a shared vision that protects the entire school. Generally, in tanks shorter than 48", the fish can spread out across the tank and still see each other, and therefore won't exhibit their full schooling potential. Point being, if your tank is smaller than a 55g, you likely won't even see that great schooling you're looking for.
 
Rummynose tetras are pretty much universally recognized as the tightest schooling fish out there.


However, how big is the tank? Fish school as a defense mechanism against predators. They like to be close to each other, so that each member of the school can see all the other members. In that way, they have a shared vision that protects the entire school. Generally, in tanks shorter than 48", the fish can spread out across the tank and still see each other, and therefore won't exhibit their full schooling potential. Point being, if your tank is smaller than a 55g, you likely won't even see that great schooling you're looking for.

FWIW, my lampeyes school in a 10 gallon. But then they're about half the size of rummynoses, so that might be part of it.
 
I'm just starting to stock a 135 tank. Wanted a tight schooling fish. Put 6 rummy nose tetras in there and they patrol back and forth the length of the tank constantly. I agree with the previous comment about them going to the top only to feed. I'm really satisfied with how they look, so am in the process of increasing the school size to 20 or so.
 
I have 13 Harlequin Rasboras in a 60g and they school very nicely. I'd actually like to get another dozen. I think that would look really awesome!
 
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