Hello TsuRyuu- Thanks for the info, and for giving such good specifics on what tanks work for Endlers. I will slip it into the table this weekend.
Hello Jenna- Sorry you are having trouble with the table.
Unfortunately, when most people in the thread or online reported on fish that did well in 10 g or less, they weren't specific about the tank size that was successful for them. When they were, I noted the successes in three tank size categories in the table: 2.5g-5g, 5g-8g, 8g-10g. The few that were specifically noted as successful in the smallest range: pygmy killifish, betta, dwarf mosquitofish, and peacock gudgeon. Most of these aren't really 'common', though
But a number of the fish listed in the table, ones that are not identified as schoaling, would prob. do well in your tank. It is a list of small fish. Frequent water changes and having a filter (TsuRyuu notes a Red Sea Nano filter on the 2.5 g described) reduces risk. Please read the last column in the table for behavioral or technical details that would be important (like, "males only" or "eats plants"), and explore online further about any species.
I agree with Tsuryuu's recc: A few male Endler's Livebearers would be happy in a small tank. Alternatively, a Betta is really beautiful in a planted tank, and can be pretty interactive (always comes and stares out at me when I sit to look at him). And, its sorta nice to know that 3.0 gallons will always seem spacious to a Betta (given they are usually sold in one cup of water). Commonly available and sturdy
But: celestial rasboras..emerald dwarf rasboras...pygmy gouramis...dwarf molly...otocinclus are possibilities.