Nelson, J.S. 1976. Fishes of the World. Wiley-Interscience, New York 416 pp. ISBN 0-471-01497-4

Estimated total number of fish species—28,000
Valid species of fishes from book —18,818
        Strictly freshwater—6,851
        Marine and diadromous –11,967
Valid tetrapods—21,100
Valid craniates (vertebrates)—39,900

Families of living fishes—450
Orders of living fishes—46
Classes with living fishes—4

Number of families of living fishes with 1 species—TBD
Number of families of living fishes with 100+ species -- TBD
Number of families of living fishes with 1000+ species -- 1
Mean number of species per family—42
Median number of species per family-- TBD

Nelson, J.S. 1984. Fishes of the world. John Wiley and Sons, New York. 2nd edition. 523 pp.
ISBN: 0-471-86475-7

Estimated total number of fish species—28,000
Valid species of fishes from book —21,450
        Strictly freshwater—8,411
        Marine and diadromous – 13,312
Valid tetrapods—21,450
Valid craniates (vertebrates)—43,173

Families of living fishes—445
Orders of living fishes—50
Classes with living fishes—4

Number of families of living fishes with 1 species—66
Number of families of living fishes with 100+ species -- 57
Number of families of living fishes with 1000+ species -- 2
Mean number of species per family—49
Median number of species per family-- 10

Nelson, J. S. 1994. Fishes of the world. John Wiley and Sons, Inc. New York. 3rd edition. 600 pp.
ISBN: 0-471-54713-1.

Estimated total number of fish species—28,500
Valid species of fishes from book —24,618
        Strictly freshwater—9,966
        Marine and diadromous –14,652
Valid tetrapods—23,550
Valid craniates (vertebrates)—48,170

Families of living fishes—482
Orders of living fishes—57
Classes with living fishes—5

Number of families of living fishes with 1 species—67
Number of families of living fishes with 100+ species -- 58
Number of families of living fishes with 1000+ species -- 3
Mean number of species per family—51

Nelson, J. S. 2006. Fishes of the world. John Wiley and Sons, Inc. New York. 4th edition. 601 pp.
ISBN: 0-471-25031-7.

Estimated total number of fish species—32,500
Estimated valid species of fishes  to end 2006—28.400
Valid species of fishes from book (to end 2005)—27,977
        Strictly freshwater—11,952
        Marine and diadromous –16,025
Valid tetrapods—26,734
Valid craniates—54,711

Families of living fishes—515
Orders of living fishes—62
Classes with living fishes—5

Number of families of living fishes with 1 species—64
Number of families of living fishes with 100+ species -- 67
Number of families of living fishes with 1000+ species -- 3
Mean number of species per family—54
Median number of species per family—12