The Sri Lankan fishermen were arrested by the Coast Guard while fishing off Kodiyakarai, Joint director of fisheries department Suburaj said, adding the Coast Guard also seized their two boats.
The fishermen were later taken to Karaikal to be produced before a court, he said.
Meanwhile, four Tamil Nadu fishermen were allegedly beaten up by Sri Lankan naval personnel off Katchatheevu.
He said the naval personnel came to the spot in fast boats, attacked the four with plastic pipes, cut the fishing nets of 20 boats and chased them away.
They also snatched the GPS equipment and cellphones from the fishermen, he said.
