Emerging species are organisms for which we have enough information, regarding biology, nutrition, morbidity, etc., to allow individuals to attempt to culture them with some difficulty. With emerging species, there will be information a culturist would like to know that is still lacking; for example, market and economic information. Only highly knowledgeable fish culturists will be successful in culturing these species. Which aquatic organisms can be considered as emerging species for recirculating aquaculture will vary with the individual’s knowledge and interest. This paper is an attempt to disseminate information on several freshwater, brackish and saltwater species that appear to meet the ‘emerging’ definition. Their inclusion as emerging species does not imply they are profitable to produce and market. Freshwater species include: barramundi, walleye, carp, white sucker, and grass carp. Brackish or saltwater species include: bay scallops, blue crab, mummichog, ornamental fish and invertebrates for the pet industry, rainbow smelt, cobia, European oysters, American oysters, bloodworms and sand worms, green sea urchins, black sea bass, and several species of aquatic plants.