Which one of the following is not a true fish?

Correct Answer :   Fin Whale

The world's second-largest animal, fin whales, are second only to blue whales in length. The species were almost near-extinction during the 20th Century due to hunting. Whaling was banned after this and for the first time since then, dozens of southern fin whales were caught feasting together recently in a "thrilling" Antarctic spectacle.

Correct Answer :   Ladakh

Scientists have discovered fossil of a rare Madtsoiidae snake from the molasse deposits of Ladakh Himalaya. The rare fossil indicates the prevalence of the species in the subcontinent for much longer time than previously thought. Madtsoiidae is an extinct group of medium-sized to gigantic snakes. They had first appeared during the late Cretaceous period and the whole group largely disappeared in the mid-Paleogene across most Gondwanan continents except for Australia where it survived with its last known taxon Wonambi till late Pleistocene.

Correct Answer :   Vaquita

The world's smallest marine mammal 'Vaquita Porpoise' are on the verge of extinction with just 10 left in their sole habitat within Mexico's Gulf of California, as per World Wildlife Data. The vaquita porpoise reproduces just once in every two years. They have been pushed to the brink of extinction after getting accidentally trapped in fishing nets and due to illegal fishing.