Lionfish: characteristics and information on this invasive species

Lionfish: characteristics and information on this invasive species
Posted on 18-05-2023

Lionfish: characteristics and information on this invasive species


Characteristics of the lionfish are fins with rays uncovered by tissue, a pattern of brown and white stripes, and two antennae above the eyes. This invasive species has invaded the Atlantic Ocean and many seas where it is not native, displacing native species.

The tropical oceans harbor an unequaled richness allowed by the warm waters. The fish that live there have striking colors, and among the most special, the lionfish stands out. In addition to having a peculiar color pattern, its fins resemble a lion's mane. This aspect serves to warn of its danger and, in fact, it classifies as one of the most poisonous fish that exist.


Lionfish Characteristics

Lionfish are those that belong to the genus Pterois , and are characterized by having pectoral and dorsal fins with very long rays, with no tissue between them at the end, reminiscent of a lion's mane, from which they get their common name. Above their bulging eyes they have a pair of horn-like antennae.

They have aposematic coloration in a conspicuous pattern of brown and white stripes that alert predators that want to eat them of possible danger, because they contain a dangerous poison .

There are 12 species of lionfish with variations between their physique and habitat. Some of the most popular are:

  • Red or red lionfish ( Pterois volitans ): measures 35 centimeters long. It has feathery fins.
  • White-finned lionfish ( Pterois radiata ): 25 centimeters long, and darker in color. It has a pinkish white chin. The spokes are completely white and give an ethereal look.
  • Soldier lionfish ( Pterois miles ): It is whiter than the previous ones, and with a more rounded head.

In the case of a fish, the question arises, can lionfish be eaten? The answer is yes. This practice helps to control excessive populations, which, as we will see later, are a real plague. For fishing to have this conservationist aspect, small fish must be removed to prevent them from reaching the reproductive stage. However, it must be done in places where they are an invasive species and with a global balance so as not to take the species to the other extreme of conservation and put it at risk.


Where do lionfish live

  • They are benthic fish , that is, they live associated with the seabed . Here they can be found among coral reefs , rocks or sea grass .
  • They blend in very well with their surroundings due to their brown color pattern, many times they manage to go completely unnoticed.
  • Regarding the geographical distribution, they are located in tropical waters . They are endemic to the Pacific and Indian Oceans , varying in regions depending on the species.
  • The lionfish is an invasive species and has been introduced into the Atlantic Ocean and eastern seas , so it is possible to see lionfish in the Mediterranean even if it is not their native area. Lionfish in Venezuela have also invaded the Caribbean Sea, as well as near Florida, in the United States. Initially it was introduced for the aquarium trade, but the situation got out of hand.

What does lionfish eat

  • In their natural environment they feed on small live fish , such as guppies, or also shrimp and crabs . They are predatory carnivores , but also generalists, eating as much as they can.
  • The technique to capture their prey is to let themselves be carried away by the current until they run into a prey and pounce on it. Others may make groups to corral together.
  • Very rare cases of cannibalism among lionfish have been recorded.
  • It is nocturnal and takes advantage of the darkness to get ahead of its prey.

Is lionfish poisonous?

Lionfish are poisonous . It has glands that connect to the outside that come out of the dorsal fin, two rays of the anal fin and two rays of the ventral fin. They are aggressive and territorial, so you should not make contact with them to avoid risks.

What is a lionfish sting and what to do?

The effect of the sting is defense only. When threatened, they expose their fins with rayed or poisonous spines to marine predators. First, the rays puncture the skin causing pain, and second, they inoculate poison that causes fever, respiratory and circulatory failure .

In case of being stung by a lionfish, hot water should be applied directly to the affected area, which will help to reduce the pain and the effects of the venom are not so serious. Then you have to go to medical authorities to check the wound.

Fortunately, the poison is not lethal in humans , but unnecessary contact should be avoided because there are more risks, such as wound infection or drowning from suffering these symptoms while still in the water.


How the presence of lionfish affects the native ecosystem

The lionfish is a pest because it reproduces with a high larval survival rate , is adept at crossing environmental boundaries, and is a predator. It has been introduced to places foreign to it and, due to its invasive nature, its populations grew excessively, altering the ecosystem balance and displacing native species . For example, the island of San Andrés in Colombia has 1 million of these fish, a fairly high number.

Specifically, the lionfish affects the native ecosystem because it preys as much as possible. A single 12-inch lionfish feeds on 10 pounds of fish a year, depleting native species and the role they play in the ecosystem. This creates a knock-on effect, because the species that feed on the fish that are now preyed on by the lionfish are left without food.

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