Rui Fish (রুই মাছ) Deshi/Local/Bil/Gher Per Kg
- Collected from trusted source.
- Weight may slightly vary.
Rui (রুই মাছ), Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. They form a sister group to the tunicates, together forming the olfactores. Included in this definition are the living lampreys, and cartilaginous and bony as well as various extinct related groups. Around 99% of living species are ray-finned fish, belonging to the class Actinopterygii, with over 95% belonging to the teleost subgrouping.
The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. They would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods.
Most are ectothermic (“cold-blooded”), allowing their body temperatures to vary as ambient temperatures change, though some of the large active swimmers like white shark and tuna can hold a higher core temperature.