From another similar post, introducing fish to a large body of water has to be done like this or else the fish don't understand or acclimate properly and die. It's a slap to the noggin like "hey wakey wakey, go find some algae to nibble on"
While these fish would be easy to catch at that time, they will taste like shit. Once they've spent some time eating something other than pellet food they taste a lot better.
So, if I understand you correctly, what you're saying is - given the quite large body of water about half a mile away from me, all downhill, I should get a giant catapult and fling some piranha.
I'll go down in history, either for the best April Fools joke ever, or if my aim is off, the best Halloween prank ever 🐟🐠🐟😁