posterior root the posterior, or sensory, division of each spinal nerve, attached centrally to the spinal cord and joining peripherally with the anterior root to form the nerve before it emerges from the intervertebral foramen; each posterior root bears a spinal ganglion that conveys sensory fibers to the spinal cord.he sensory division of each spinal nerve, attached centrally to the spinal cord and joining peripherally with the ventral root to form the nerve before it emerges from the intervertebral foramen.
Freshwater. Many freshwater fish average about 1 to 3 years of life. Some of the more popular species with this short life span include fantail guppies, swordtail platy, mollies, rainbow fish, hatchet fish, corydoras catfish, some cichlids, rasboras and tiger barbs. There are also several fish that live around 3 to 5 years, with proper care and feeding.
Usually, smaller fish have shorter lives. For example, bettas live for an average of two years, and killifish may only live for a year. On the other hand, larger fish lead longer lives. Loaches can live 10 years or longer. Goldfish vary in size depending on their habitat, but they can live for decades. Most domestic fish do not live as long as they could. Improper care and poor environment usually lead to early death in many species. Although goldfish can live 20 years or longer, many fail to last a single year.