The Red Lionfish (Pterois volitans) is a striking marine fish that can grow up to 30 cm in length. It is known for its long, venomous spines and its distinctive color pattern of red-brown and white stripes. One of its most noticeable features is its impressive array of up to eighteen large, fan-shaped pectoral fins, which are separated by dorsal spines.
In Thailand, the Red Lionfish is regarded as an invasive species. It likely spread to the region through aquarium releases or escapes. Once introduced, it has established itself in coral reefs and marine environments, where it poses a significant threat to local ecosystems by preying on native fish and invertebrates.
Behavior
The Red Lionfish is a nocturnal ambush predator that uses its fan-shaped pectoral fins to trap prey and its venomous spines for defense, often displaying its spines and flaring its fins when threatened; it is generally solitary but may sometimes gather in loose groups, especially where food is abundant.
They are one of the most invasive species in our oceans, comprising 92% of the invasive fish population. They can adapt to various temperatures and are found in many ocean environments. Their resilience is evident, as they can live as deep as 300 meters.
Feeding and Diet
The Red Lionfish mostly eats small fish, crustaceans, and invertebrates. It uses its venomous spines to stun and capture prey. This fish hides in the reef and waits for unsuspecting prey to come close before striking. Its effective hunting strategy and very strong appetite allow it to have a big impact on the local marine life.
The Red Lionfish has venomous spines that can pose a serious risk, and there have been cases where they’ve caused fatalities in humans. Despite this, there's no need to fear them if you give them space. They are not aggressive towards divers but will raise their fins to signal distress and try to escape. If they feel trapped or threatened, they can charge with surprising speed.
Reproduction
The Red Lionfish is a prolific breeder, spawning multiple times a year and releasing large quantities of eggs into the water. During the breeding process, males perform elaborate courtship displays, including spreading their fins and engaging in rhythmic swimming to attract females. Once a pair is formed, they swim together and release eggs and sperm into the water column.
The female Red Lionfish can release up to 30,000 eggs in a single spawning event, significantly boosting their rapid population growth and spread. The eggs are fertilized externally by the male. After fertilization, they drift with the ocean currents until hatching into larvae. While both males and females play roles in reproduction, the male's courtship display and role in ensuring successful fertilization are especially crucial.
Predators
In their native Indo-Pacific habitats, Red Lionfish do face some natural predators like larger groupers, snappers, and sharks. However, in areas where they have been introduced, often have fewer natural predators, which contributes to their status as an invasive species.
Where to Find Red Lionfish on Koh Tao
You can spot the Red Lionfish while scuba diving in few dive sites around Koh Tao, check out dive sites like:
