The 800-Pound Grouper in the Room: Asymptotic Body Size and Invasiveness of Marine Aquarium Fishes

The global trade in aquatic wildlife destined for home aquaria not only has the potential to be a positive force for conservation, but also has a number of potential risks. The greatest and most documented risk is the potential to translocate species that will become invasive in a new habitat. Although propagule pressure can influence species invasiveness, a high percentage of documented marine aquarium fish that are invasive in the US are uncommon in the trade. Here, the covariation of size with species invasiveness was assessed using a web scraper to collect size, price, life history characteristics, and behavior data from five internet retail stores for 775 species of fish. Fish that routinely exceed 100 cm in total length are traded, nevertheless are typically sold at sizes much smaller than their theoretical maximum. No economic benefit from the sale of species that will outgrow tanks and have a high risk of being released was found. Large fish, including groupers that can achieve weights of 800 pounds, will continue to enter the trade because the growth of aquaculture for commercial food markets is making it easier to acquire these species that also have appealing small life stages, making it easier and less expensive to bring these species into the aquarium trade. The entire trade should consider taking concerted action to limit the trade in fish that are likely to become invasive.