Join Date: May 2011
Location: Elk Grove, California
Diamond tetras are a variant of the regular neon tetra. Your 20 has females, right? If you get a school of 10, they should be fine in a 20 with female bettas. I successfully kept 10 neons in a 10gal before so that many should be fine in a 20.
You can put a baby in a breeder's net in the 20 but you'll probably run into the same problem as with a 1 gal: confined space. Exactly how big is your baby? Is it really teeny or is it larger than that? I kept my baby in a 1.75gal kritter keeper for about a month and then released her into the sorority and she's doing fine. But then, my girls are crazy mellow 99% of the time soo . . . My best recommendation is head to Wal-Mart and get a good-sized Rubbermaid shoebox type container for the baby.