Some fish names what they call in Tamil nadu and their English names:

Seer fish is called Vanjaram in Tamil.
Barracuda is called Sheela in Tamil.
King Fish - Mavalasi
Gaint Trevally - Parai
Spotted Trevally - Pulli Parai
Little Tunny - Soorai
Yellowfin Tuna - Kerai
Indian Mackerel - illa(eye-la)(or Kanagnkelluthi)
Indian goat fish - Kendal (not kendai)
Murret: Kendai
Cuttle fish - kanawai
Squid - Oosi kanawai
Lobster - Singa Erra
White prawns - Vella Erra
Barramundi - Koduva
Marine cat fish - Kelluthi
Leather skin - Thera (variety of parai)
Whip tail sting ray - Thirukkai
Indian Halibut - Pothal
Shark - Sura
Scorpion fish - Sori kalavan
Puffer fish - Pelachi
Red Snapper - Sankara , Kalavayan.
Seabass - Koduvai
Cod - Panna
Spade fish - Seepu Thiratai
Butterfly fish - Pattai
Parrot fish - Killi Meen
Pomfret - Vavwall