Fish Stomach

Ventriculus

The muscular acidic sac of the digestive tract - present in most predators, absent or reduced in many herbivores and detritivores.

Region: Trunk Unique to: all

📖 Overview

A fish stomach is a diagnostic tool for diet. Predators have well-developed, expandable, acid-secreting stomachs; herbivores like carp and many minnows lack a true stomach entirely, relying instead on long intestines for slow enzymatic digestion.

🧬 Structure

Muscular chamber lined with gastric glands. Shape varies: J-shaped (predators), Y-shaped (carnivores), or absent (agastric fish).

⚙️ Function

Mechanical breakdown, acid denaturation, protein digestion via pepsin, temporary food storage.

🐠 Variations Across Species

Cyprinids (carp, minnows) are agastric - lack a true stomach. Sharks have valvular stomachs. Cod have expandable stomachs allowing swallowing of prey larger than head width.

✨ Fun Fact

A cod can swallow prey larger than its own head because its stomach and jaws expand dramatically. Full-grown Atlantic cod have been found with intact skate and small sharks inside.