Earlier in his career, McKay focused on introduction and translocation of exotic freshwater fish in Australia.He extensively researched the Australian Aquarium Industry. Later, he also extended his study to fish that were not exotic but just unusual.
He is recognised as an authority on the fishes of the Family Sillaginidae McKay, R.J.1985.A Revision of the fishes of the family Sillaginidae. Mem.Qd.Museum, 22(1):1-73.
McKay, R.J. 1992. FAO Species Catalogue 14. Sillaginid fishes of the world (Family Sillaginidae). An Annotated and Illustrated Catalogue of the Sillago, Smelt or Indo-Pacific Whiting species Known to Date. FAO Fisheries Synopsis, No. 125, Vol. 14. 1992. 87 p., 137 figs.
McKay, R.J., 1984. Introductions of exotic fishes in Australia. In Courtenay, W.R. Jr. and J.R. Stauffer, Jr. (Editors). Distribution, Biology and Management of Exotic fishes. The Johns Hopkins University Press, Baltimore, Maryland, USA., 1984, p. 177-199
Arthington, A.H., D.A. Milton and R.J. McKay (1983). Effects of urban development and habitat alterations on the distribution and abundance of native and fresh- water fish in the Brisbaneregion, Queensland.Austra1- ian Journal of Ecology 8.87-101
Arthington A.H., R.J. McKay and D.A. Milton, 1983. Effects of urban development and habitat alteration on the distribution and abundance of native and exotic fish in the Brisbane region, Queensland. Aust. J. Ecol. 8. 87-101.