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Bighead carp (Hypophthalmichthys nobilis)


(Pterois volitans and P. miles)

Report this Species!

If you believe you have found this species anywhere in Pennsylvania, please report your findings to iMapInvasives by submitting an observation record.

Species at a Glance

The red lionfish (Pterois volitans) and the devil firefish (P. miles) are species of invasive lionfish that were introduced by humans and are now causing negative impacts on marine ecosystems and reef habitats. Their venomous spines and unique appearance may deter potential predators, making them unrecognizable as prey and allowing their populations to increase.


Lionfish have distinctive brown or maroon and white stripes covering the head and body that alternate from wide to very thin and sometimes form a “V”-shape. They have fleshy tentacles above the eyes and below the mouth. Membranes of the fins are often spotted. The pectoral fins are fan-like, while the strong, venomous dorsal spines are long and separated. The anal fin also has sharp venomous spines. Adult lionfish can grow as large as 46 cm (18 in) while juveniles may be as small as 2.5 cm (1 in) or less.

Similar Species

In their native range, the red lionfish and the devil firefish can be differentiated by counting the fin rays; however, in their invasive range, these two species can be virtually identical and positive identification can only be achieved through genetic analysis.


While found in almost all marine habitat types, lionfish prefer warm marine waters of the tropics. They have been found in water depths from 0.3-305 m (1-1000 ft) on hard bottoms, mangroves, seagrass, coral, and artificial reefs.


Initial introduction of both species was thought to have occurred during Hurricane Andrew in 1992 when at least six lionfish escaped from a broken beachside aquarium near Biscayne Bay. The continued release of unwanted lionfish by aquarium hobbyists is thought to be the cause of additional introductions and the range expansion of the lionfish.


Lionfish are native throughout the South Pacific and Indian oceans and their native distribution covers a very large area. They were first detected in south Florida waters in 1985 and were documented as established in the early 2000s. They are now well established throughout most of the Caribbean to Cape Hatteras, North Carolina. Juveniles have also been found as far north as New York and Rhode Island, although they are not expected to be able to survive the winter in colder northern waters.


Note: Distribution data for this species may have changed since the publication of the Mid-Atlantic Field Guide to Aquatic Invasive Species (2016), the source of information for this description.

Environmental Impacts

The lack of natural predators is allowing lionfish to reproduce year round and quickly increase in abundance. They are voracious predators, consuming over 50 species of fish, including some economically and ecologically important species. They pose a threat to many native reef fish populations through direct predations as well as competition for food and resources. They can also reduce the abundance of herbivorous fishes that keep seaweeds and macroalgae from overgrowing corals.


Information for this species profile comes from the Mid-Atlantic Field Guide to Aquatic Invasive Species (2016).

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