Planted Tank Enthusiast
Join Date: Apr 2013
Location: Honolulu, Hawaii, USA
Its more down to you and your willingness to do the work involved taking care of X number of tetras. You could play it safe (easier) with only a dozen, or go big with 40, but then have work (water changes, filter cleaning, etc.).
40 neons in long tank would be a sight to see... But, lots of work.
Father of the Princess Zelda.