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Reproduction
Yolk-Sac Nutrition
The initial energy reserve of fish larvae - a nutrient-rich sac that sustains them for days to weeks before they can feed independently.
System: Digestive Level: Beginner Discipline: Physiology
📖 Overview
Fish hatch with a yolk sac still attached - carrying the last of the maternal investment in lipids and proteins. As the sac is absorbed, the larva must transition to external feeding. This critical window is the highest-mortality period in the fish life cycle. Aquaculture larviculture stands or falls on getting first-feeding right.
✨ Fun Fact
Some deep-sea fish have yolk sacs so large that hatched larvae drift for months while absorbing them - reaching effective juvenile size before ever needing to feed.