Why New Pond Fish Vanish: Predators, Hiding, and Cannibalism

Predators

• Crows: Absolutely eat small fish. They spear them from the edge.
• Herons: Major koi/goldfish predators.
• Raccoons, cats, mink: Nocturnal hunters.

Cannibalism

Large koi/orfe will eat fish under a few inches. Orfe are more actively predatory; koi mostly inhale small fish accidentally while feeding.

Hiding Behavior

New fish are masters of concealment. They can disappear for weeks in a planted pond. Before assuming the worst, observe at dawn/dusk with polarized glasses.

Protection

Net the pond. Provide dense plant cover (floating and submerged). Consider a motion-activated sprinkler (Scarecrow) for herons, though raccoons may learn to avoid it.