Fahlanders has mainly concerned his research with studies of the shape of the atomic nucleus, its core patterns and electromagnetic properties, as well as forces between protons and neutrons in nuclear nuclei. Among his discoveries was when he and his research team in 2016 verified the discovery of element 115, which had previously been discovered in Dubna, Russia in 2003.
Fahlander was elected as a member of the Royal Physiographic Society in Lund in 1998 and as a member of the Royal Swedish Academy of Sciences in 2006.