You might have to slope the area around the pond back toward the water....when aro jumps out, the slope, will hopefully direct him back into the water!
Depending where you are located, might have to watch out for racoons and other wildlife!
I might of found out Jardini's problem!
If this is your setup, CATS AND FISH DON"T MIX!
http://toronto.kijiji.ca/c-pets-accessories-75-GAL-fish-tank-fishes-ARO-GAR-PALCO-price-update-W0QQAdIdZ34128226