I voted no because there are fish and especially inverts that can live happily in such a small aquarium, but there are other sides to this hobby- nano and pico. pico marine contain only corals, and maybe just a couple of inverts, if that, depending on tank size. Nano marine is over 5 gallons so we can discount that. But I know there is planted FW nano, small tanks that are either purely plants or plants with a couple of fish. I would prefer, however, that they are not sold in such numbers as they are, and they come with suitable guidlines and warnings. Because it takes quite an experienced aquarist to put together a nano/pico aquarium and stock it with livestock (or not) responsibly