My creek had fewer game fish in it this spring due to the loss of most of my deep pools. I did observe a big crop of small fish last weekend, but when I looked closer, it was actually thousands of big bullfrog tadpoles. Apparently, without abundant fish predators my population of tadpoles exploded.

I thought I should probably google that to see what effects the bullfrog population. I was surprised to read that gambusia can be big consumers of eggs! There are lots of types of frog eggs that they find tasty. Many toad eggs are either unpalatable or even toxic. I like your idea of some toad habitat pools with gambusia, but I would check with one of the habitat restoration experts to confirm that the gambusia will not eat the Houston Toad eggs in your pond and pools.