Stomach acquire different shapes according to the availability of space in the body cavities of different fishes.
- ANTERIOR – CARDIAC STOMACH
- POSTERIOR – PYLORIC STOMACH
All the fishes do not pocess a true stomach as it is almost absent in various herbivorous fishes like Labeo rohita,Catla catla etc.In such fishes, the anterior part of the intestine is swollen to form a sac like structure called intestinal bulb.A true stomach is present in the carnivorous and predatory fishes e.g Channa striatus, Mystus seenghala etc .
Carnivorous fishes: Stomach is generally sac-like and thick walled in Carnivorous and predatory fishes.
Omnivorous fishes: Stomach of omnivorous fishes is also sac like .e.g. Puntius sophore, Cyprinus carpio etc. In some fishes like Hilsa ilsa,Gudusia chapra, stomach is reduced in size but is greatly thickened to become gizzard like for trituration of food
