I hope the other posters are right, and that I'm wrong. But I've been told that patching a liner is next to impossible. There is the issue of glue, heat, and weight, and at our pond store, they make it sound like no matter how well you do it, if it's not factory-done, it's gonna leak. Maybe not fast, but water will find a way to seep through some part of the repair.
That said, depending on how big the pond is and how much liner you would need to buy, it may well be worth trying to patch it, instead of buying a new liner.
And I hope your fish will be OK, in temporary holding tanks. It's so stressful for them.
Good luck on the repair.