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Focusing on the Family: Pteroinae – Lionfish
Spines along the jawline
Venomous spines of the Lionfish
Inhabiting all tropical and most subtropical seas the family Scorpaenida represents a large array of fishes.
These include stonefish, leaf fish, waspfish, lionfish, crocodilefish, velvetfish and scorpionfish, which are all featured on this site.
Most are benthic creatures and they rarely swim.
All Scorpaenida possess venomous spines of varying potency.
Lionfish, like most Scorpaenida, lay eggs of jelly like masses, which are pelagic and float to the water’s surface.
Once hatched the juveniles spend many months in the water column.
Venomous dorsal spines
The juvenile lionfish then slowly descend to the bottom where they grow into ferocious sit-and-wait predators, feeding on fish and crustaceans.
Common characteristics of lionfish include a large head and mouth in relation to the rest of their body.
Lionfish also possess armour like ridges around the cheek, as seen left.
They also possess venomous spines along the dorsal and anal fins, as seen right.
Each has two venom sacks at the base, which are squeezed together when contact is made, thus injecting the poison.
The more spines that make contact, the more venom is received.
Family: Pteroinae – Lionfish
The most mobile of the order, often seen hovering above the substrate, coral blocks and submerged debris.
False Eyes of the Lionfish
They are quite stunning due to their long dorsal fins and elaborate pectoral fins pictured left. As a result they are sought after creatures for the aquarium trade.
This elaborate striped coloration is a warning sign to predators that they are poisonous, its also thought that the lines confuse those that might wish to eat them by breaking up the body form.
Some species have “false eye” spots (image right), meant to confuse predators as to the where abouts of the creatures true eyes as this is usually the focus of an attack.
They are formidable hunters and when disturbed they often make little effort to swim away, instead slowly turning their back towards the intruder.
If they feel under attack they would jolt backwards impaling the predator on the venomous spines.
Species: Pterois volitans – Common Lionfish
As the name suggests, the Common Lionfish this is a common species in certain areas, namely the Red Sea and Indo Pacific.
A fairly large creature, the Common Lionfish grows up to 35cm in length.
The body is covered with red to black bands on a pale background.
The Common Lionfish feeds mainly on other fish.
Night divers beware: they are attracted to torch lights and we have witnessed people almost sitting on them, unaware of their presence.
Common Lionfish are particularly good photo subjects as they’re often seen in mid-water, although when approached they turn their back on you in preparation for defense, so don’t get too close.
Species: Pterois antennata – Spot-fin Lionfish
Long spines of Spot Fin Lionfish
Regularly encountered by divers the Spot-fin Lionfish is often seen resting on coral heads and rocks.
This species is easily identified by the long spines on their pectoral fins and is named for the blue spots on the membrane of the fin.
The Spot-fin Lionfish can grow up to approx. 20cm in size.
They inhabit coral reefs throughout the Indo Pacific.
Species: Dendrochirus zebra – Zebra Lionfish
The body of the Zebra Lionfish has a typical pattern of dark red bands, with alternating large and narrow band.
Often confused with the Dwarf Lionfish, the Zebra Lionfish’s pattern bars are more defined.
When fanning its pectoral fins, as seen, image right, note that long filaments are absent, differentiating this species from other members of this family.
The Zebra Lionfish can grow up to 20cm in size and lives at depths ranging from 3m to 100m.
Species: Parapterios heterurus – Blackfoot Lionfish
On first appearance this relatively small lionfish bares many similarities to other family members of the species.
Striking bright blue lines and dots
However, upon closer inspection it’s easily identified by striking bright blue lines on the inside of its pectoral fins.
It also has dots on the inner part of the ventral fins, as can be seen below.
These are displayed as a warning to possible predators.
Between the second and third spine of the tailfin is an extended filament which can be seen in the image below.
Long Filament on Tailfin
This feature is a very quick way of identifying your find as a Blackfoot Lionfish.
A deep water species, usually not encountered by divers.
Sadly, the best chance for marine enthusiasts to see this fish is to hang around the jetty when the bottom trawler boats bring in their bycatch.
Our observation suggests it to be nocturnal species and a very rare find.
However, once discovered they can be seen regularly in the same area, but only at night.
Photographed here beneath Seaventures Resort – Mabul Island, Celebes Sea.