There are no top US pet retailers that would advise aquariums under 1 gallon for betta fish, at least according to their betta fish care literature.
This is a positive outcome of Petco changing its suggested minimum betta fish tank size from 1/4 gal to 1 gal on its "Betta Care Sheet" in October.
Manufacturers like Aqueon, Hygger Aquarium, Penn Plax, Marina, and more are producing aquariums under 1 gallon, some as low as 0.23 gal per fish. These kits often use images of bettas on the packaging and give owners the impression that they will enjoy them as permanent homes.
Betta fish are physically resilient and can endure poor conditions, so these manufacturers create tanks that provide unhealthy environments for betta fish to endure.
Manufacturers must accept that as consumers continue to learn about betta fish aquarium needs (5+ gal, heating, filtration, etc.), not only will the demand for these kits decline, but these tanks will only look worse for their brands.
It is unnecessary to manufacture tiny betta fish-specific aquariums when bettas need 5+ gal.
Producing them is a waste of resources!!