Our garden ponds are artificial environments. This means that they need maintenance to keep the conditions acceptable for fish. Yes, carp (Koi) and goldfish are pretty tough but they do much better with the water temperature, pH and hardness in their optimum range and with a minimum of waste build up in the pond. Hydrogen Sulfide kills things very easily when in high enough concentrations. Parasites can knock out most of your fish in a few days if not caught early. We want our fish to be happy and healthy, not struggling to survive. The same goes for feeding, a healthy diet keeps them alive a lot longer.

I think your only chance of catching most of these fish is to use a Seine net, but a one acre pond is pretty big, which is going to make the job a bit more difficult. Your friend will probably need to either drain the pond down to a manageable level, or perhaps use small boats or very long lines to maneuver the net. It'll probably take several passes to round them up. Maybe someone else can come up with some other ideas. I know of no traps that can catch that many fish in such a large area.

eek! I was going to ask if the bumps looked fuzzy thinking maybe a fungal infection. But I guess you have it under control. I hope the Proform LA works for you. I dont know about it, but judging by your '(ouch)' I'd say its expensive. btw, my Koi jumps too..man can they jump! And nothing is wrong with him. When I first got mine I had read in many dif places that Koi are known jumpers, so I never thought twice about it. I love it when I am right at the pond when he jumps. You will be treating the whole pond correct? I dont agree with just treating the sick fish in a hosp tank, or whatever. Better to treat the whole pond and rid the pond of the parasite, then to have to keep treating fish over and over again individually by not getting to the root of the problem. Good luck and I hope all goes well.

My friend built his pond under a 40 foot Black cherry tree and hasnt lost any fish in the 4 years he's had it . I made the mistake of planting a dwarf Plum tree near my pond . It is now as high as the roof of my house and drops tons of plums into the water . The rotting fruit make the fish drunk . They do eat some of it but what a pain trying to scoop out all the plums and seeds . Its to big to net the pond or the tree . Also in the spring the top of the water is white with flower pedals and then the leaves in the fall . Plant something else . Rick