I was tired of wasting water adding it to my swimming pool, so I converted pool to a pond. I have a small filter with waterfall to keep the water aerated, and I added 10 shiners about 4 years ago. Pool is now a haven for all types of animal life, and I do nothing other than keep pond pump functioning. Several generations of toads have used the pond to reproduce, countless minnows, and now a bullfrog recently found my pond. Bullfrog is eating the toads (4 lived in the pond, two were killed and I relocated the other two that showed obvious signs of being in the frog's belly (partially digested rear legs)). I have countless dragonflies, birds, squirrels, toads, and now a bullfrog. I'm so happy that I converted pool, and I am surprised that the pond is thriving with very little effort on my part. Pic shows bullfrog on floating planter with a couple of toads (one killed by frog, one still alive). Apparently, frog eats toads and then spits them out alive after a bit (maybe toads are too big?). Frog is hard to photo as it is very timid and submerges when I get close, but I managed to capture an image, sorry about the quality. I rinsed off the living toads and relocated them to a rock pile in the corner of my yard.