Originally Posted by Oldfishlady
In an experiment I conducted (non-scientific) I found that ammonia started to show up in a 1gal unfiltered container, bare bottom, no live plants with one adult Betta-fed 2 times a day with a quality flake food with zero left over...ammonia 0.25ppm at about the 72h mark and even less in 4gal....
Wow, interesting. It's less ammonia than I expected and yet at the same time, still a surprising amount produced by one little fish. It really illustrates how fast the stuff builds up, though, so let it be an incentive to keep up with those water changes.
OFL, you really are the great fish guru.