Fish and meat
Fish is the dominant kind of protein, and is cultivated in ponds and fished with nets in the fresh-water rivers of the Ganges delta. Almost every part of the fish (except fins and innards) is eaten; the head and other parts are usually used to flavor curries. The head is often cooked with dal or with cabbage.
More than forty types of mostly freshwater fish are common, including carp varieties like rui (rohu), koi (climbing perch), the wriggling catfish family of tangra, magur, shingi and the pink-bellied Indian butter fish, the pabda katla, magur (catfish), chingŗi (prawn or shrimp), as well as shuţki (small dried sea fish). Chingri could be of varieties - kucho (varieties of shrimp), usual (prawns), bagda (tiger prawns), and galda (Scampi).
Salt water fish (not sea fish though) hilsa (hilsa ilisha) is very popular among Bengalis, can be called an icon of Bengali cuisine. Ilish machh (hilsa fish), which migrates upstream to breed is a delicacy; the varied salt content at different stages of the journey is of particular interest to the connoisseur, as is the river from which the fish comes - fish from the river Pôdda (Padma or Lower Ganges) in Bangladesh, for example, is traditionally considered the best. To some part of the community, particularly from West Bengal, Gangatic Ilish is considered as the best variety.
There are numerous ways of cooking fish depending on the texture, size, fat content and the bones. It could be fried, cooked in roasted, a simple spicy tomato or ginger based gravy (jhol), or mustard based with green chillies (shorshe batar jhaal), with posto, with seasonal vegetables, steamed, steamed inside of plantain or butternut squash leaves, cooked with doi (curd/yogurt), with sour sauce, with sweet sauce or even the fish made to taste sweet on one side, and savory on the other. Ilish is said be cooked in 108 distinct ways. Also, there are different ways of cutting vegetables, which is important for the dish you are cooking. A cut for the "Chochhori" cannot be used for the "Dalna". Each different food has its own cut of vegetable, to keep with the cooking time and procedure of each dish.