A study was conducted at River Mayo Ranewo and River Lau, Taraba State Nigeria. The two rivers empty into the Upper Benue Basin. A survey of visual encounter was conducted within the two wetlands from June to August, 2014. The fish record was based entirely on landings of fishermen, number of canoes that land fish was counted, types of nets and baits used on each sampling day. Fishes were sorted into taxonomic groups, identified to family/ species level, counted and weighed in groups by species. Other aquatic organisms captured by the fishermen were scallops, turtles and frogs. The relative species abundance was determined by dividing the number of species from a site by the total number of species from all tributaries/sites. The fish were preserved in 2% formaldehyde solution and taken to the laboratory, were identified through keys of identification to African fishes and field guides. Shannon-Wieiner index of species diversity indicated that the diversity was highest at River Mayo Ranewo than River Lau. Results showed that at River Mayo Ranewo, the family Mochokidae recorded the highest (23.15%), followed by Mormyridae (22.64%) and the least was the family Lepidosirenidae (0.04%). While at River Lau, the family Mochokidae recorded the highest occurrence of (24.1%), followed by Bagridae (20.20%), and then Mormyridae, which also was the second highest in River Lau, with 18.46% occurrence. There was no occurrence of Malapteruridae and Osteoglossidae (0%) in River Lau, but the least occurrence was the family Gymnarchidae (0.04%). According to the result from the t-test, the fish composition was not significantly different (p≤0.05).
 L. O. Emmanuel and O.O. Modupe, Fish diversity in three tributaries of River Ore, South West, Nigeria. World Journal of Fish and Marine Sciences,2010, 2(6): 524-531. ISSN 2078-4589.
 C. D. Smith and J.S. Pontius, Jack Knife estimator of species richness with S-plus Journal of Statistical Software, 2006, Vol 15, Issue 3, Ppl-12.http://www.jstatsoft.org/.
 Nolan, K.A. and J.E. Callahan (2005). Beachcomber Biology: The Shannon-Wieiner Species Diversity Index. Pp 334-308. In: O’Donell, M.D (Ed.) Tested Studies for Laboratory Teaching, Volume 27. Proceedings of the 27th workshop/ conference of the Association for Biology Laboratory Education (ABLE).
 Bakawale, S. and R.R. Kanhere (2013). Study on the fish species diversity of the River Narmada in Western zone. Research Journal of Animal, Veterinary and Fishery Sciences, Vol. 1(6): 18-20. ISSN 2320-6535.
 Oruonye, E.D. (2014). The challenges of Fishery Resource Management Practices in Mayo Ranewo Community in Ardo Kola Government Area (LGA), Taraba State, Nigeria. Global Journal of Science Frontier Research: D Agriculture and Verterinary, Volume 14, Issue 3, Version 1.0: pp 14-24.
 Thiel, R., A. Sepulveda, R. Kafemann and W. Nellen (2006). Environmental factors as forces structuring the fish community of the Elbe estuary. Journal of Fish Biology, 46(1): 47-49.
 Waltham, N.J and R.M. Connolly (2007). Artificial waterway design affects fish assemblage in urban estuaries. Journal of Fish Biology, 71(6): 1613-1629.
 Jordan, S.J., M.A. Lewis, L.M. Harwell, and L.R. Goodman (2010). Summer fish communities in Northern Gulf of Mexico estuaries: Indices of ecological condition. Ecological indicators, 10(2): 504- 515.
 Farias, I.P. (2000) Total Evidence; Molecules, Morphology and the phylogeneticsof Cichlid Fish, Journal of Experimental Zoology, 288:76-92.
 Moritz, T. and K.E. Linsenmair (2001). West African fish diversity-distribution patterns and possible conclusions for conservation strategies (In: Africa Biodiversity: Molecules, Organisms, Ecosystems, Springer, 2001).
 Gheerbrant, E. and J.C. Rage (2006). Paleobiogeography of Africa: How distinct from Gondwana and Laurasia? Palaeogeography, Palaeoclimatology, Palaeoecology, Vol. 241.
 Mbinkar, D.L. (2007). Evaluation of the conservation significance of two lacustrine wetlands of the Upper Benue basin, Nigeria. Unpublished Ph.D. Thesis, Department of Biological Sciences, Ahmadu Bello University, Zaria. 215pp.
 Odo, G.E., N.C. Didigwu and J.E. Eyo (2009). The fish fauna of Anambra river basin, Nigeria: species abundance and morphometry. Rev. Biol. Trop. (Int. Journal of Trop. Biol., 57(1-2): 177-186. ISSN-0034-7744.
 Soyinka, O.O., M.P. Kuton and C.I. Ayo-Olalusi (2010). Seasonal distribution and richness of species in the Badagry Lagoon, South-west, Nigeria. Estonian Journal of Ecology., 59(2): 147-157.
 Olaosebikan, B.D. A. and Raji (1998). Field guide to Nigerian Freshwater Fishes. Decency Printers and Stationaries Ltd. 106pp.
 Holden, M. and W. Reed (1991). West African freshwater fish. Longman GroupLtd. UK. 68pp.
 Reed, W., J. Burchard, A.J. Hopson, J. Jenness and I. Yaro (1967). Fish and fisheries of Northern Nigeria. Published by the Ministry of Agriculture, Northern Nigeria. Printed by Gaskiya Corporation, Zaria, Northern Nigeria. 226pp.
 Lewis, D.S.C. (1974). An illustrated key to the fishes of Lake Kainji. ODA London. 106pp.
 Shannon, C.E. and W. Weiner (1963). The Mathematical Theory of Communication. U. Illinois, Urbana, Illinois. pp 117.