Digestive system of a fish:
- A fish’s digestive system is adapted to their dietary habits.
- Fish, being cold-blooded have a simpler digestive system compared to warm-blooded animals like mammals.
- Fish’s digestive system includes
- Mouth
- Esophagus
- Stomach
- Pancreas
- Liver
- Gall bladder
- Intestine
- Anus
| Digestive System of fish | Description |
| Mouth
| · The mouth of fish can vary in size and shape depending upon the feeding habits of the fish. · Mouth of Some fish have specialized structures such as teeth or beaks for capturing and processing of their prey. · The mouth being the entry point for food, allows the fish to initiate the process of ingestion of various types of prey. · Depending on diet, the mouth’s structures (teeth, beaks, etc.) break down food into manageable pieces for further digestion. · Some fish secrete limited saliva to initiate the breakdown of carbohydrate. · Some species have gill rakers that filter out larger particles before water reaches the gills. |
| Pharynx | · The pharynx is present just behind the mouth · It serves as a passage for both food and water. · In some fish, the pharynx contains gill rakers, which helps in the filtration of large particles before the water passes over the gills for respiration. |
| Esophagus | · It is a muscular tube that connects the pharynx to the stomach. · It assists in the movement of ingested food towards the stomach through peristaltic contractions of digestive tract. |
| Stomach
| · The stomach of fish varies in structure depending on their diet. · Herbivorous fish have longer and more convoluted stomach for the breakdown of plant material. · Carnivorous fish have a short J-shaped stomach designed for the rapid digestion of protein-rich food. · The stomach act as a temporarily site for the storage of food. · Stomach mixes the stored food material with gastric secretions to form chyme. · Gastric glands present in the stomach secrete enzymes for the initial breakdown of proteins. |
| Intestine
| · Length of intestine varies in fish species depending upon their feeding habits. · It is typically longer in herbivorous fish, enabling them to breakdown the complex plant matter. · In carnivorous fish, the intestine might be shorter as protein digestion is less complex. · The intestine absorbs nutrients with the help of villi and microvilli. · The intestinal walls secrete enzymes for carbohydrate, protein, and fat digestion. · Nutrients are absorbed into the bloodstream through the intestinal lining. |
| Liver | · The liver in fish plays a vital role in the digestion and metabolism of nutrients. · Liver performs following functions: · The liver produces bile for the emulsification of fats for better digestion. · It detoxifies harmful substances and waste products. · It regulates nutrient levels and stores glycogen and vitamins. |
| Pancreas | · The pancreas of fish secretes various enzymes such as amylase, lipase and proteases for breaking down of carbohydrates, fats, and proteins. · It also releases bicarbonate to neutralize stomach acid in the intestine. · It also produces hormones like insulin and glucagon for the regulation of blood sugar. |
| Rectum | · Final portion of the digestive tract is known as rectum. · Its function is to temporarily stores waste material and excess water before it is eliminated through the body. |
| Anus | · Feces and excess water are eliminated from the body through the anus. |