These are also known as the bony fishes. They have an endoskeleton of cartilage which occurs in the embryo form and have a bony cartilage in the adult form. They are cold blooded. The cycloid and ganoid scales form the exoskeleton and are mesoderm in origin. They do have a gill cover so the gills are covered. The process of excretion and respiration occurs by a pair of kidneys which are mesonephric and with the help of gills respectively. They have multiple cranial nerves. The ammonia is main waste product. Their heart is double chambered with well developed SV and CA. It is 3 chambered in lung fishes. It has a well formed renal portal system. They have an external mode of fertilization. They have an air bladder which helps in the floating and can be oviparous or ovoviviparous. They have no cloaca but do have external nares. The internal nares may occur in some cases like lung fish. They have a homocercal fin which means in which there are no lobes of different kinds are present.
The labio rohita is also known as rohu. It is a carnivorous and a surface feeder. It resides in the sluggish river and also acts as a popular dish. They have a tail where there are no lobes of different kinds are present and are known as homocercal tail. They do not have scales. The fish has a sub terminal mouth and is covered by the thick lips. It also has thread like structures known as barbles. The anabas is also known as climbing perch. It can survive without the water for some time. During this time it respires through the accessory respiratory organs which are present near to the gills. It is a carnivorous and a predator. The earthworm serves as their food and they come out of water and look for them. It is not able to climb the trees. The birds pick it up and drop them on tress and this is referred as a climbing perch. They have gill covers. The pectoral fins have pelvic fins under them. It also acts as a source of food. The dorsal and anal fins are long. The mystus is also known as the cat fish. It occurs mainly in fresh water in rivers, ponds etc. It is a carnivorous and has a fin where there are no lobes of different kinds are present and are known as homocercal fin. They do not have scales. It also has thread like structures known as barbles which are 8 in number. The exocetus is also known as the flying fish. It also acts as a source of food. It goes into the air but do not fly. It can rise up to 6m high. The gliding movement of fish is possible due to the presence of pectoral fins. It occurs on the tropical and warmer areas.
The hippocampus is also known as sea horse. It has neck and head which resembles a horse. It has a prehensile tail and it swims upright. They have no caudal and pelvic fins. They show the phenomena of sexual dimorphism. The male has a brood pouch which has a space where the females lay egg. So they have a male parental care. Its skin is used to make some ornaments and it occurs in the tropical and temperate areas. The solea is also known as flat fish. They have asymmetrical head and are laterally compressed. The pectoral and pelvic fins are retarded. The dorsal and ventral fins are long but are not in contact with the caudal fin. They have a couple of eyes which occur on the same side and they help to bear a water pressure.
