My koi are disappearing?

[orozco]

I live in southern california and built a pond just bought 2 koi and the second day I had the koi were still there but 2 hours later I check it 1 disappeared...what happen.

[BIGgourami]

despite their sterotypic image.. cats rarely mess with fish inside of water.. much less a 4-5 inch koi..

the most rational guess would be a heron.. raccoons tend to theive at night.. while herons are diurnal predators

deepening the pond (if possible) or grating the top of it are two possible options.. protective grates are made to be rather aesthetically pleasing nowadays.. though somewhat expensive

[lksproodle51]

Well mine did to but i found out that the local racoon's were getting to them so i covered it with a see through mesh. alot of critters like to eat fish