They would probably prefer algae. If you don't have algae in your tubs, you might consider buying those algae wafers. You should be able to get them at Walmart of any petstore.

Thanks Nancy, but I have no intention of feeding or keeping them.
I play around with hybridizing waterlilies, they are in my seedling tubs and stripping them bare.
In order to get them out, I will have to pull hundreds of seedlings first.
Corrie

In that case leave the tadpoles and let them eat your lillies.

Someone on another board suggested Rotenone.
Worked perfect.