Which Sanskrit text permitted the local Brahmanas to eat fish?

The Sanskrit text that permitted local Brahmanas to eat fish was the Brahmanical law texts. These texts, which include works like the Dharmashastras, provided guidelines for social conduct, duties, and customs. In certain regions, especially in eastern India such as Bengal, local practices and environmental conditions influenced dietary habits. Since fish was a staple food in these regions due to the abundance of rivers, the Brahmanical texts adapted to local customs and allowed Brahmanas to consume fish. This shows that religious rules were not always rigid but could be flexible to accommodate regional traditions and practical needs.