I have larger size rock gravel.
I have a hang on back Aquaclear filter with an adjustable flow.
I keep three adf's in a 29 gallon tank with a number of fish. My tank is heavily planted. In a ten with only frogs I would probably do 6-8.
They like hiding spots. Little caves and plants are good.
I feed mine zoomed pellets in an oyster shell.
I have a journal on bettafish.com called betta testing, where I talk a lot about my adf's and have a lot of pictures.