I use a half wine barrel with goldfish in it for watering....and... feeding.

I submerge a large watering can in the water and transfer the water to a small pot for the trees.

I use water from my pond as well.

One thing to keep in mind is that suitable water for goldfish and koi are not compatible with acid loving tress like azaleas. It will kill them in the long run.

Azalea......management...... killed me. Also the heat. But mostly the management requirements.

How do you know the fish water was not part of it?