No pump is needed, or even desired imo.

Don't know about the beta. Mosquitofish are great for that. Or mosquito Dunks.

A tub is good for lilies. For many others I just laid down a liner and some boards to form edges. Just 6-12" deepe depending on what I was growing. For marginals I kept them in regular plastic pots and just set them into the liner deal so they just had wet feet.

Thanks! Perhaps then I will have two tubs - one filled for lillies and duckweed and one only partially filled for the marginals. Will the mosquito fish survive with no aeration? One reason I was thinking beta is that I know they don't need aeration pumps. Where I would like to hide these tubs is a little removed from electricity access. If I had needed pumps I was going to have to think of somewhere else to hide them.

Again, thanks for your input.

Cheers
M

Mosquitofish are low O2 type fish. I'd call them the gold standard of mosquito control. They do have limits, just as I'd assume Betas have limits.