Question

Fish which eradicates mosquito larvae is:
A. Rohu
B. Anabas
C. Clarius
D. Gambusia

Answer 1

Fish are cold-blooded vertebrate animals that can be found in both freshwater and saltwater all over the world. Hagfishes, sharks, bony fishes, and other fishes belong to the superclass Agnatha (jawless fish) and the phylum Chordata, which contains hagfishes, sharks, and other bony fishes. All fishes, with the exception of the Opah, are cold-blooded vertebrates. Gill slits on the side, skeleton supporting chord, and a tail are all characteristics of fish. Ichthyology is the study of fishes, and it has shed light on the role of fish in the world's food supply.

Complete answer:
Option A: Freshwater ponds, lakes, rivers, and streams are common habitats for Labeo rohita (Rohu). It eats algae and aquatic plants and is primarily herbivorous and bottom feeder. It breathes through its gills and frequently comes to the surface of the water to gulp air into its air bladder.
So, option A is incorrect.
Option B: Climbing perch (Anabas testudineus), commonly known as Walking Fish, is a small Asian freshwater fish of the Anabantidae family known for its capacity to live and move outside of water. The climbing perch is a labyrinth fish that breathes air.
So, option B is incorrect.
Option C: The planktonic food is preferred by this omnivorous fish. Insects, insect larvae, pupae, fish, and fish carcasses are some of the other foods it eats. It also has a carnivorous nature. The method of propagating these fish is common throughout the tropics.
So, option C is incorrect.
Option D: Gambusia affinis is classified as a larvicidal fish because it feeds on mosquito larvae exclusively. It is an effective method for mosquito biological control.
Option D is correct.

Therefore, Option D is correct.

Note:
It has been used as a mosquito-control agent all over the world. Following its arrival in the early, it has become a problem in many rivers. It's a highly predatory fish that consumes the eggs of economically significant fish and preys on rare indigenous fish and invertebrates in addition to reducing mosquitoes. It’s a small, heavy, strong creature that's dull grey to brown in colour and has a terminal and upward-pointing mouth designed for feeding at the water's surface. The dorsal fin is tiny and rounded, and it starts behind the anal fin.