Most fish cannot live on land because they have no lungs and cannot absorb oxygen from the air. Their gills can absorb oxygen dissolved in the water. So fish can only live in water.

Fish are the oldest vertebrates. The offspring of some crosses with different chromosome numbers are still fertile. They inhabit almost all aquatic environments on Earth, from freshwater lakes and rivers to saltwater seas and oceans.

Fish are divided into two superclasses: the jawless superclass and the jawless superclass. The jawless superclass includes Cyclostomia and Onychophora, and the jawed superclass includes placoderms, cartilaginous fishes, and ray fins. Most fish in the class Fish are cold-blooded vertebrates that live in water all year round, use gills to breathe, and use fins to assist body balance and movement. Extended information

Some fish can survive on land, such as African lungfish, mudskipper, and climbing bass that can survive on land for a long time, and snakehead fish, eel, and gar breathe with a single swim bladder.

1. Lungfish

Live in fresh water. In addition to breathing with gills, they can also breathe with their swim bladders instead of lungs. Even in dry periods, they burrow into the mud. During aestivation, the dormant period can last for several months, but there is a time limit. The reason why the lungfish can live outside the water, as its name suggests, is that it can use its "lungs" to breathe.

2. Mudskippers

Mudskippers are geniuses among fish. They spend much of their lives not in the water. The area where they live is covered with mangroves, and they are happy to climb up tree trunks or branches. They use their pelvic fins as suckers to grab onto trees and their pectoral fins to crawl upwards. Mudskippers have small openings around their gills that can hold a breath of water, much like we can hold a breath.

Baidu Encyclopedia - Fish

Baidu Encyclopedia - Lungfish