I am planning to drain my 20'x35' pond in order to install a liner. There are approximately 50 goldfish and koi in the pond, ranging from ver small to 10 inches in length. I need to make some sort of temporary holding tank to keep the fish while I do the work on the pond. I estimate it will take 4-6 weeks to complete the work. Any suggestions on what sort of tank to use? Thanks,

Do you have any kids? Would they like to have a swimming pool to swim in? I'm thinking that one of those inflatable swimming pools would work - don't they come (or have available) a filtration system? Use it to hold the fish, and after the fish go back in the pond recycle it for the kids.

I thought about the swimming pool idea.

I also have several bullfrogs. Any way of keeping them around when I drain the pond?

If the bullfrogs are native to the area, I wouldn't worry about it, they'll find their way back after you're done. There are places where you can buy bullfrog tadpoles, I know Jones sells them, but they aren't cheap.