Classification of fish  based on feeding habit

1. Herbivorous Fishes:

• They consume about 70% unicellular algae, filamentous algae and aquatic plants.
• In addition to plant material these fishes also consume 1-10% of animal food and mud.
• The common examples are Labeo species Osphronemus goramy, Sarotherodon mossambicus etc. Herbivorous fishes have long and coiled intestine.

2. Carnivorous Fishes:

• The fishes in contrast to herbivore have shorter gut, the intestine is straight, very little coils are present.
• Some of the carnivores possess intestinal caecae. They prey on small organisms and consume high percentage of animals such as copepods, dafnia and insects.
• The examples of carnivorous fishes are Walla go attu, Mystus seenghala, Mystus cavassius, Mystus vittatus, Channa striatus, Channa marulius, Channa punctatus, Notopterus chitala, Rita rita,

3. Omnivorous Fishes:

• Omnivorous fishes like Cyprinuscarpio, Cirrhina mrigala, Puntius, Clarias, etc. are consuming both plants and animals.
• The rotifers, mud and sand are also found in the alimentary canal.
• Their gut length intermediates between carnivorous and herbivorous fishes.

4. Detrivorous or Plankton Feeder:

• They consume detritus along with zooplanktons and phytoplankton’s.
• The arrangement of gill rakers are such that it filters them from water.
• The examples are Catla catla, Hilsa ilisa, Cirrhina reba, and Hypopthalmichthys molitrix. They are both omnivorous and carnivorous.