My pond gets super cleaned about twice a year - fall and spring. I drain 99 % of the water out, and have clean hose water running in while the dirty water is being pumped out. My goldies (and other fish) are usually in about 8 inches of water in the bottom of the pond so it makes it a bit easier to catch the ones I want. They have no place to hide (insert evil laugh here). I know, I know, the whole no more than 50%
water change - treat the water first - etc. I have a fish thumb when it comes to my pond. Either that, or I have been extremely lucky my whole life. Our water is good as is, straight from the hose, with no treatment necessary. If I need to move my fish, I fill a new container with straight hose water, catch the fish, and put them in the new water. When I am done with them and they can go back in the pond, I pick them out of the container - usually just with my bare hands - and back in the pond they go. I haven't lost a fish yet doing that.