The Solovetsky Islands are located in the central part of the White Sea (Arctic Ocean). The species composition and distribution patterns of freshwater ichthyofauna were studied in various watersheds of the two biggest islands of the Solovetsky Archipelago, Bolshoi Solovetsky and Anser, affected differently by eco nomic activities. The research was performed in 1989-2012; in total, 40 lakes were studied. Two main groups of species were defined in regard to the original and historical data, aboriginal and introduced. Aboriginal species include rainbow smelt (Osmerus mordax), perch (Perca fluviatilis), pike (Esox lucius), roach (Rutilus rutilus), burbot (Lota lota), crucian carp (Carassius carassius), sticklebacks (Gasterosteus aculeatus, Pungitius pungitius), and ruff (Gymnocephalus cernuus). Sterlet (Acipenser ruthenus), brown trout (Salmo trutta), ven dace (Coregonus albula), tench (Tinca tinca), and goldfish (Carassius auratus) are the introduced species. The origin of whitefish (Coregonus lavaretus) and ide (Leuciscus idus) remains unknown. The current distribution of all studied species is patchy and varies significantly between the lakes, and the origin of particular species should be found individually for each lake.