Lionfish

The scientific name given to the lionfish is Pterois but in colloquial terms, it is also referred to as turkey fish, butterfly cod, zebrafish and firefish that belongs to the genus of venomous marine fish. They belong to the indo-Pacific and belong to the family of scorpionfishes, scientifically described as Scorpienade of order Scorpaeniformes. They are a wide range of species with various conspicuous warning colours such as white, red, creamy or black bands with pectoral fins and spikey venomous fin rays. 

As lionfish stings, the fins produce venoms when coming in touch with any living surface and produce painful and puncture wounds but they don’t result in fatal. The commonly studied species of the genus Pterois are Pterois miles, Pterois radiata, Pterois volitans. Among the above three species, Pterois miles and Pterois volitans have recently been classified as significant invasive species that affect the bioregions and the invaded habitats adversely in terms of ecological, environmental and economic damages. They are found as an invasive species in West Atlantic, Caribbean and Mediterranean oceans.

The main characteristics that segregate the lionfishes from other fishes are that they have elongated dorsal fin spines and enlarged pectoral fins. Each species is different from the other in terms of their appearances as they individually bear different patterns of stripes that are zebra-like as seen. If they feel disturbed they spread their fins around and if they feel more threatened or attacked then it aggressively attacks back with the lionfish spines. As the lionfish sting is venomous by nature and puncture wounds over the surface being attacked causes a lot of pain. Lionfish due to their variation in phenotypes has always been a showstopper for the fish pet enthusiasts and in various aquariums. A picture of a lionfish (Pterois volitans) is illustrated below for a clearer understanding.

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Description of Lionfish

Usually, the base coat of almost all the species of the lionfish is either maroon or brown in colour and have zebra-like white stripes or bands that are spread all over their body from head to the spines and fins stretching to its rare ends. They also have a pair of tentacles that are above their eyes but below their mouth and are fleshy by nature. They have fan-like pectoral fins and there are 13 numbers of dorsal spines that are elongated and separated from one another. The number of dorsal fin rays ranges from 10 to 11 and they are fairly soft with 3 anal spines and 6 to 7 anal rays that are also soft in nature. An adult lionfish can grow up to 18inches in length but the juvenile lionfish is only about an inch long or sometimes it is less than that. Lionfish have scales on their body that are either oven or elliptical and have soft edges. The vast majority of the lionfish have red colour as a base coat with black and white stripes.   

Types of Lionfish

Till now there are 12 kinds of lionfish are known out of which few important lionfish with their characteristics and features are described below:-

1. Red Lionfish / Red Sea Lionfish

The scientific identification of the red lionfish is Pterois volitans that is a coral reef marine specious and possess venom. Red lionfish have a pattern of white stripes that are alternating with maroon, brown and black stripes throughout their bodies including the fins and the dorsal and anus rays. They are one of the largest species among the lionfish that can grow up to 47 cms (18.5) inches but the newborn red lionfish is just about an inch long. The average lifespan of a redfish is about 10 years.

The red lionfish are native to the indo-pacific ocean particularly the western and central Pacific and at the coast of Western Australia. In the early 21st century they have been accidentally introduced to the Gulf of Mexico, the Eastern seaboard of the American states, the Caribbean sea and the Western Atlantic where they are considered an invasive species. 

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2. Andover Lionfish

The scientific name given to this lionfish is Pterois andover that is colloquially known as zebra lionfish and fire lionfish. They have a white base colour with alternating brown strips and few black spots can also be seen spread out unevenly in the entire body of the lionfish. They usually stay in family groups but sometimes also dwell singly hovering over the ground in the crevices and caves in upside-down positions during the morning. They usually hide their face inside the rock crevices or caves. But they are very active at night in the search of prey. Their beautiful feathery dorsal fins are highly venomous in nature and they rise their fins up straight as a warning if disturbed. The fins are usually their defence weapon and the lionfish sting may cause death to various other coral reef species and thus frighten them away. They are usually 23 cms long and are found at the depth of 3 to 70 meters in the Western Pacific.

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3. Spotfin Lionfish

The biological name for the spotfin lionfish is Pterois antennata which is commonly known as broad barred fish and is very similar to that of red lionfish. Its typical habitat includes coral reefs and lagoons and is the natives of the Western Pacific ocean. They are now introduced to the Indian Topical Ocean as well. The tentacles of the sportfish have different characteristics than the other lionfishes as the projecting part of it above the eyes termed as appendages resemble more like an antenna. Because of this feature, the species got its biological name as the same. They usually grow up to a length of 20 cms.

They are often active hunters during the night in the lagoons and primarily feeds on the crabs and the shrimps. To hunt down its prey it spreads its pectoral fins as far as possible to trap the species in them. In the morning it hides inside the hollows of the rocks and the caves and rests against the vertical wall in the rocky coral surfaces. It usually faces its head upside down towards the floor. 

The species is oviparous, which means it lays eggs in severe tens and thousands in number. They all hatch within few days and get spread within the current for several weeks.

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4. Luna Lionfish

The scientific name of the luna lionfish is known as Pterois lunulata dragon’s beard fish that are native to the topical water of the Western Pacific ocean. These lionfish have a scale in the centre part of the body with the alternating white and brownish band running from the head to the tail of the body. The scales are given an illusion of the net-like structure over the patterns of the body. They possess pectoral fin rays that have V-structured markings with the soft dorsal fins that are spotted. The adult possesses the caudal and anal fins that are absent in the juvenile luna fish.

They are associated with the marine reef and have an average depth range of 132 to 172 meters. The maximum length a luna lionfish can attain is 25 cm. It has 13 pectoral rays and thus is often confused with P. russellii. The mid-aged luna fish do not have any spotted pattern on their body but as an adult, they acquire the spotting. They primarily feed on fishes and crustaceans. They mostly love to dwell on soft-bottom substrates at a moderate depth of water or on the outcrop of the reef. 

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5. Devil Firefish

Pterois miles, commonly known as devil firefish or common lionfish is often confused with its close relative red lionfish as they both are natives to the Indo-Pacific ocean. The devil firefish belong to the ray-finned fish. They grow up to 35 cm long that is about 14 inch in total length. They have 13 long and strong spines at dorsal fins. They possess 9 to 11 soft rays and the anal fins have six to seven soft rays with 3 strong spines. They appear to be very feathery as the pectoral fins have separated wing rays that are broad and spread. The pectoral fins are winged like structures. The colour of the devilfish ranges from reddish to tan or greyish with a large number of thin vertical bars that are of darker shades and are present all over their body including the head. Their head is less angular as compared to the other lionfish. They are nocturnal by nature as they hide in the morning and is active hunters at night. They generally feed on small fishes and sometimes on small crustaceans.

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6. African Lionfish

The African lionfish is also known as frillfin turkeyfish and deepwater firefish. It has a biological name as Pterois mombasae. They are normally found in the Topical Indian Ocean and Western Pacific ocean. Unlike other lionfish, they often prefer to dwell in typical soft-bottomed areas of the ocean. They are often conjugated with other invertebrate growth like sponges. They grow up to a maxim size of 20 cm in length and is of moderate commercial value. 

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Ecology and Behaviour

The average lifespan of all the species of the lionfish ranges from 5 to 15 years. They usually represent a very complex courtship including mating behaviours. The female lionfish are seen releasing two big clusters of eggs that are filled with mucus and they contain as many as 15000 eggs at a time. They do not prefer to live in groups and are solidarity species and only during mating they come together where there is one male in mating with several female lionfish. Sexual dimorphism of lionfish can only be seen during the reproduction process. The female lionfish produces two giant masses of eggs that are fertilized by the male before they get through the current on the surface of the water. The embryos have a characteristic of releasing mucus that functions like adhesive that helps them strick to the intertidal rocks and corals before they are hatched. Females are seen to lay more eggs in summers than in winters. A female can lay up to 30,000 eggs at a point in time. 

Native Habitat of Lionfish

The lionfish is a native dweller of the Indo-Pacific ocean, though their range is decreasing rapidly in those areas and the reasons are still unknown. They are the dominant predators who aggressively prey on small fishes and several vertebrates that becomes a big threat to the natural competition of marine life in the ocean. They are mostly found dwelling around seaward edges that are present in the coral reef, in the burrows of the rocky substrates, in lagoons or on mesophotic reefs. As they are very flexible and quickly adapts to the changing environment of the ocean water in terms of temperature, depth and salinity of the water they became a very easy invasive species.

They are often found in the harbours or in the turbit areas in the inshore and are very hostile in nature and are often behave territorially towards other coral reef species. They prefer to stay in shallow water. They are often habitat in an average of 100m (330ft) depth of water. Though some of the species of lionfish were even found at a depth of 300m. Many universities that have released studies on the lionfish have been seen stating that the fish is very aggressive and attacking towards the researchers and the divers in general. P. volitans and P. miles are native to the tropical and subtropical regions of southern Japan and southern Korea. They have been widespread in Australia, Indonesia, Micronesia, most of the South Pacific ocean and French Polynesia. They are now found in the Indian ocean as well from Sumatra to Sri Lanka and also in the red sea.  

Diet of Lionfish

A study involved the dissection of almost 1400 lionfish stomachs caught from Bahamian to North Carolinian waters to know their diet and feeding habit. It has been noticed that they mostly prey on small fishes, molluscs and small invertebrates in a very large amount. The stomach of some of the specimens also included six or seven various types of prey. The amount of prey that was studied in the stomach of 1400 lionfish fishes suggested that they are actively feeding between 7:00 to 11:00 AM and eventually the feeding amount decreases as afternoon precedes. 

As the lionfish possess a bilateral swim bladder that is specialised to provide very controlled and precise navigation to a particular location in the water columns. In addition to the navigation, it also allows the fish to alter the centre of gravity of its body to swiftly attack the prey. The lionfish spreads its large pectoral fins as it approaches the prey and swallows its prey at once in a single motion. As they approach the prey, they blow a jet of water to disorient the targeted prey (which is usually the smaller fish) so that it faces the lionfish. This is an effective practice the lionfish follow to head-first capture that increases the predatory practice. 

Predator and Parasites

The adult lionfish is the primary predator of the smaller ones as they mostly feed on them. Thus the adult lionfish is cannibalising in nature. They usually have very few natural predators because of their fins that release venom that is sometimes deadly or usually painful for the other aquatic species trying to prey on lionfish. There the large groupers of marine life such as tiger groupers, scientifically known as Mycteroperca tigris and another Nassau grouper scientifically identifies as Epinephelus striatus largely prey on lionfish. Also, some of the moray eels that belong to the family of Muraenidae and Fistularia commersonii which is commonly known as blue-spotted cornetfish also prey on lionfish.

It is also believed that the sharks if trained to prey on lionfish can feed on them without any harmful effects on their spines. In 2011, the Park officials belonged to Roatan Marine Park were believed to have trained a bunch of sharks to hunt down the lionfishes in order to control the invasive population of the species in the Caribbean Ocean as it was disturbing its ecological balance as a dominant species over others. Even in Malaysia, the Bobbit worm that is considered an ambush predator has been filmed to prey on lionfish to feed on them. Though the reason for massive predating on the larvae and the juvenile lionfish is still unknown but has been a primary factor for limiting the population of the lionfish in their native habitat.

There are no or very less growth of parasite on the body of lionfish is observed and is very infrequent. But the parasites that are seldomly seen on few species of the lionfish are leeches and isopods.

Interaction with Humans

Along with the Caribbean sea coast and the Western Pacific ocean all the other reef- dwellers except the lionfish is non-venomous in nature. Thus the lionfish have very distinctive characteristics of possessing venom that they pass through the spines of the fins. Due to the venom, it makes them excellent predators and often becomes a greater danger to the divers and the fishers. The venom that is injected by the Pterois into the human body negatively effect by uncertain muscle contractions and altering the heart rate. It has the most adverse effect on rabbit blood pressure. It is because their venom has nitric oxide that is released into the body of the species that is being stung by the lionfish. Due to the release of nitric oxide, particularly the human body undergoes systemic alterations such as extreme pain, nausea, vomiting, fever, breathing difficulty, dizziness, convolution, headache, numbness, redness around the area being stung, heartburn, diarrhoea and excessive sweating. 

Very rarely the prolonged effects of the venom can cause heart failure, temporary paralysis of limbs and death. Though there haven’t been any large number of fatal cases registered so far because of the lionfish stung. Mostly the risks of mortality are high with minors, elderly people, people with low immune systems and people who are allergic to such kind of venom. Though the venom in moderation doesn’t affect much to a healthy adult some species of lionfish are known to produce a larger quantity of venom that may cause several days of pain and discomfort in the body.

This venom is also known to aggravate allergic reactions in the body. Thus the venom of the lionfish can prove to be a severe danger to the life of an allergic person. Allergic people have been seen to have a life-threatening condition of anaphylaxis that often requires immediate medical attention. The major allergic conditions that are witnessed in lionfish venom victims are swelling of the tongue, heavy breathing, a certain drop of blood pressure, chest pain, excessive sweating, runny nose and slurred speech. All of these need immediate medical care or can be fatal if kept untreated for a prolonged period of time.