How many neon tetras?
 

Hey, just wondering how many neon tetras I could put in a 20g long. It would be a lightly planted species only tank with probably a piece of drift wood in it. I might out a ghost shrimp or two in it but I doubt that would make a difference.

A whole bunch. Twenty or thirty if it was lightly planted, more if you have more dense vegetation. Neons are tiny and have a very small bioload, which is countered by live plants. Also, ghost shrimp have a nearly negligible bioload so feel free to add some to the tank.

Sweet, I might just do it. I love neons and the 3 I have need some friends.

yeah I agree I think 25 is the perfect number

for a 20 gallon tank

Yes. With their low bioload you can really pile them in. I always advise people to get the biggest school of neons and fish like them they possibly can. The bigger their group the more interesting their behavior and more beautiful they are. One or two neons can get lost in a tank. A school of twenty is a center piece.