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Muscular Anatomy
Fish Musculature (Red vs White)
Musculi corporis
The dual-muscle system of fish - dark red muscle for endurance cruising, pale white muscle for burst power.
Region: Trunk Universal in fish Unique to: all
📖 Overview
A cross-section of a fish reveals two distinct muscle types arranged in nested cones (myotomes). Red muscle - oxidative, mitochondria-rich, lipid-fuelled - runs sustained cruising along a strip near the lateral line. White muscle - anaerobic, glycolytic, glycogen-fuelled - drives explosive burst movements before fatiguing quickly. Ratios vary by lifestyle: tuna up to 30% red, flounder nearly all white.
🧬 Structure
Nested cone-shaped myotomes separated by connective sheets. Red muscle: narrow strip along the flank; white muscle: the bulk of the flesh.
⚙️ Function
Red: continuous cruising and migration. White: escape bursts and predatory strikes.
✨ Fun Fact
The dark stripe on the side of a sardine or tuna is red muscle. It carries the fish through open-ocean migrations of thousands of kilometres - powered by oxygen and lipid, not glycogen.
🔗 Related Muscular Structures