Ice fishermen utilize several mechanical and practical techniques to prevent their fishing holes from freezing over during sub-zero ambient temperatures. Common methods include using insulated hole covers or bucket lids that trap warm air directly over the water surface, deploying commercial surface-agitating bubblers or small pond aerators that maintain continuous water movement, and manually skimming newly formed ice crystals away with a specialized slotted ice spud or skimmer scoop. In unattended set-up shacks, thermal insulating foam rings and chemical anti-freeze shields are also deployed to maintain open water access.