My dad did that setting up a new pond. He went "cheap" and bought liner from the hardware store used in bathrooms. Killed all the goldfish he put in there from our other pond. Yes we are sure the liner killed them. It had some kind of nasty chemical added to it probably to inhibit mold and stuff. After the goldfish died, my dad still wasn't convinced it was'nt fish safe and the liner may be okay. So I took out everything and floated one of those breeding traps with a few guppies. Within a couple hours all guppies were dead...Don't get frustrated just learn from your mistakes. I hope at least some of your fish survive. Good luck.