A fish hatching jar (also called an egg hatching jar or Zug jar) is a specialized container used to incubate fertilized fish eggs. Water flows continuously upward through the jar, keeping the eggs gently suspended, well-oxygenated, and free of debris.

Common uses

  • Hatching tilapia eggs
  • Trout and salmon eggs
  • Carp eggs
  • Catfish eggs (in some hatchery systems)
  • Many other freshwater fish species

Features

  • Transparent plastic or glass body for easy observation
  • Conical (funnel-shaped) design
  • Water inlet at the bottom
  • Overflow outlet at the top
  • Gentle upward water flow to circulate the eggs without damaging them

Typical sizes

  • 1–2 liters: Small-scale or hobby hatcheries
  • 5–10 liters: Small commercial hatcheries
  • 20 liters or larger: Commercial fish farms

Benefits

  • High oxygen levels for developing eggs
  • Reduces fungal growth by keeping eggs separated
  • Removes dead eggs and waste through water circulation
  • Improves hatch rates when properly managed