Yes Maithil Brahmin traditionally eat fish and mainly goat meat, chicken is also popular in younger generations.
Fish is used culturally in all occassions like Marriage and Death.
Maithil Brahmins (Brāhamaṇas is the Sanskrit term), a community of highly cohesive, traditional Brahmins who form part of ancient Vedic Brahmins. Maithil Brahmins are a Hindu Brahmin community from the Mithila region of India and Nepal. They are one of the five Pancha-Gauda Brahmin communities.[1]In India, the Maithil Brahmins reside mainly in Bihar and the neighbouring states of Uttar Pradesh, Jharkhand and West Bengal.Like many other Hindu castes, the Maithil Brahmins trace their origin in the legends of Ramayana. During the Mughal period, they migrated westwards to the Braj region.In the 1960s and 1970s, the Maithil Brahmins became politically significant in Bihar. Binodanand Jha, Lalit Narayan Mishra, and Jagannath Mishraemerged as prominent political leaders of the community. Under the Chief Ministry of Jagannath Mishra, many Maithil Brahmins assumed important political positions in Bihar.
i can not say that gaur and maithil get married.but u can get married in same gotra but shaka must be differ.
Maithil Kavi Kokil
Abhaya Nath Mishra has written: 'Shrotriyas of Mithila' -- subject(s): Maithil Brahmans
maithil are illigamate son of ravan an ashur,they are magician and tantrik.thier shudra king darbhanga have ashur ravan blood. thier is story that they are actually shudra and thier mother is prostitute.they are descent of brahmin father and prostitute shudra mother. saryupareen brahmin are real brahmin,saryupareen are brahmin who found acroos river saryu,