Pond draining success stories to reassure my mom that I'm not going to murder her frogs

It is time to swap out the water in my mother's pond, and as the only able bodied adult handy, that means me. My current plan involves a long hose to siphon off the water, but Mom is concerned about accidentally sucking up an important frog. Mom is still mourning the loss of a three legged bullfrog in a storm *four years ago*, so you can imagine her feelings if I accidentally murder one. My parents, both of whom use rollators and can't spend long periods of time standing, spend about an hour a day standing at the edge of the porch and watching these frogs, who have full names and detailed bios. (The rest of the day is divided between bird watching, commenting on the movements of their lawn roomba, gardening, watching the beehives, and scaring the shit out of me by climbing up ladders with chain saws)

I'm under a time limit here, because she wants nice clean water for the tadpoles and will do it herself if I don't. This is a woman who just had major bowel surgery to remove some cancer. She's also the most frequent ladder offender. Either I empty this thing on Tuesday afternoon, or I take her to the hospital to get her stitches replaced Wednesday night. She promised me she wouldn't do it herself, but she wouldn't promise me she wouldn't do it at all, and that means she's enlisted my semi mobile father who can't bend over.

Help? It's not a big pond, but I still don't want to bail it out by hand. Has anyone ever emptied a pond with a hose siphon and *not* killed the frogs? Please tell me about your successes so I can pass the good news on to mom!