I'm thinking of getting guppies in a 20 gallon if I don't feed them anything special will some survive on their own? I will have have fern anchored down hornwort float and maybe some water sprite or frog bit.
I will probably start with 2, male and most likely already pregnant female. A friend of mine has a 100+ ( not very sure ) gal. With oscars that he could feed any extra guppies, I plan on selling them to an LFS.