My wife has a large industrial plastic bucket out the back, in which I tip my waste water after a water change. She uses this on her potted plants.

I've aslo found it handy as it regularly has quantities of Mosquito lavae. I just scoop up a batch in a fish net to provide my fish with tasty live treats.

In line with that topic, live food that is, I have gone in the back yard and dug up some earthworms before. I cut em into little bits, and the fish loved them.