Today we are going to talk about Spider fish. This is the common name that it has and it belongs to the Trachinidae family. Its scientific name is Trachinus drake and like him Lion fish, stone fish y Scorpion fish It is poisonous. It is well known for causing accidents to people on beaches that are shallower.
In this post we will talk about the characteristics and way of life of the spider fish. We'll also discuss how to treat a sting from this poisonous fish. Want to learn more about this fish?
Key features
This fish is characterized primarily by its behavior toward its prey. To surprise them, it hides under the sand and goes unnoticed. It is buried leaving out the eyes and part of the headThis makes it very difficult to distinguish with the naked eye.
In general, it is a fairly sedentary fish and lives in hidden waters up to about 50 meters deep. It can also be found below 100 meters, although it is more common in shallow coastal waters with sandy or muddy bottoms. Specimens can be found with sizes that They range from 15 to 45 centimeters in lengthDepending on the variety and age, the size may vary.
In terms of appearance, it has a fairly elongated, compressed body. Its mouth is large, as is its head. It tilts slightly upward so it can watch for prey while hiding in the sand. As with all species around the world, morphologies develop to better adapt to their environment. This turn of the head allows it to see from its shelter under the sand and attack quickly.
Its first dorsal fin is quite short and is where they are found the poisonous spines (usually 5–7 spiny rays). Also It has a poisonous spine on the edge of the operculumThe second dorsal fin is long and made up of soft, non-poisonous rays that aid it in swimming. These structures are key to its defense, as the spiderfish It ruffles them when it feels threatened.
Thanks to these spines, they can protect themselves from their natural predators. They are more likely to be attacked while swimming, as they otherwise spend their time hiding in the sand. When disturbed, they will raise their dorsal fin as a warning, and with a sudden movement of the head, they can drive their spines in with enough force to pierce through resistant materials.
Color, food and habitat
Its color is green with dark spots on the head and some yellow and blue lines on the sides. This fish has a cryptic colorationThis is a coloration that all animals with the ability to camouflage themselves possess. The interplay of shades of green, dark spots, yellow, and blue allows them to go unnoticed in the middle of the sea. This gives them a huge advantage over their enemies.
Let's now talk about its diet. The spiderfish's main diet is the smaller fish found on the seabed. It also consumes crustaceans and other benthic invertebrates.To hunt its prey, it buries itself in the sand, leaving only its eyes exposed. It can see its prey very accurately thanks to its upwardly tilted head. It has great patience to wait for the right moment to attack another animal.
Although he spends much of the day buried, At night it becomes active and can swim freely., even prowling in slightly more pelagic areas in search of food. This behavior explains why it is sometimes observed off the substrate.
Its area of ​​distribution extends from the waters of the Mediterranean to the Atlantic. The habitat is found in those areas where sandy and muddy bottoms abound.They are not found in other types of seabeds, as they cannot hide to hunt. They are most commonly found near the seabed at a depth of about 50 meters. However, in the summer, they can frequently be seen on shallow beaches and near shores. This causes some problems for bathers.
Because beach sand simulates the seabed where they usually hunt, they burrow beneath the sand to wait for prey. When people are swimming or wading near the shore on shallow beaches, they are attacked by these fish. The bite is quite poisonous. as discussed below.
Identification, species and differences with similar fish
The species of the genus Trachinus They belong to the Trachinidae family and are known for their venomous spines. They are small to medium-sized fish with an elongated and laterally compressed body, with short caudal peduncle and high-positioned eyes, which improves their vision when they are semi-buried.
They have two dorsal fins: a first cut with poisonous thorns y a long second dorsal with soft raysThe pelvic fins are located in front of the pectoral fins, a useful feature for identification. In addition, They have a poisonous spine on the operculum; various studies indicate that these lateral spines may be especially active.
Hay several species described in the genus, standing out in nearby waters:
- Trachinus drake (common spiderfish)
- Trachinus araneus
- Trachinus radiatus
- Trachinus vipera (small spider)
They are widely distributed throughout the Eastern Atlantic’s most emblematic landmarks, the Mediterranean Sea’s most emblematic landmarks, the Cantabrian Sea and areas of the Black Sea, also present on the north coast of Africa. They receive numerous common names depending on the region: white spider, rock spider, viper fish, wild pout, scorpion or salvage fish, among others.
It is advisable not to confuse them with species of the family Uranoscopidae (skyscrapers), which have larger, flatter head, protractile mouth and the poisonous spine located behind the operculum (In Trachinidae, the spine is located above the operculum.) Recognizing these differences helps avoid mistakes when identifying them on the coast.
Reproduction and dangers of spider fish
Because it is very territorial, during mating seasons becomes much more aggressiveNumerous unprovoked attacks on swimmers and divers have been reported. This is because they believe they are going to invade the spawning or mating territory.
The months in which it spawns are from June to August. Therefore, it coincides with the time when there are more bathers and divers.
Although this fish is from the open sea and is more typical of warm waters, it is affecting them global warmingGlobal warming is increasing the average temperature of marine waters. As a result, this species is being displaced toward the coast. There are increasing reports of attacks and poisonous stings by the spiderfish on swimmers.
Typically, the sting occurs when swimmers unwittingly step on it. It's important to remember that the spiderfish may be buried underneath, and we may inadvertently step on it. Most injuries occur to unwary swimmers or anglers who dare to handle the spiderfish out of the water. Even if the spiderfish is dead, its spines can continue to inject venom for some time..
Prevention on the beach and during fishing
The best strategy against spider fish is prevention in bathing areas and when handling accidental catches:
- Wear water shoes (booties) on fine sand beaches and surf zones.
- Shuffle walk near the shore so that the vibration will scare it away if it is buried.
- Avoid shallow sandy areas during low tide and during hours of greater sunlight, when it is more likely to remain half-buried near the shore.
- Never put your hands in the sand without visibility in areas where bites have been recorded.
- If caught in nets or rods, handle with tweezers or unhooking pliers; never with bare hands and avoid pressing the first dorsal and the operculum.
- Consult lifeguards on areas with regular presence and follow their signs.
What does the poison do?
The poison of this fish It has glycoprotein origin and is a vasoconstrictor. There is no specific antidote in clinical practice. In addition, hemolytic and neurotoxic properties, with a very painful local effect and potential to cause systemic symptoms. This venom is thermolabile (inactivated by heat) around 50–60 ºC, which underlies part of the initial treatment.
Among the damage it can cause are pain in the bite area, fever, vomiting, respiratory failure, seizures in some cases, and skin reactions such as swelling and redness. Vasoconstriction can cause paleness and edema that progresses from the site of inoculation. In cases without timely treatment, tissue necrosis may occur. The first risk, if the sting occurs underwater, is drowning due to intense pain and disorientation.
The bite is characterized by extremely intense pain that can persist for 2 to 24 hours (sometimes more), and may be accompanied by dizziness, sweating, headache, nausea, dyspnea or heart rhythm disturbances in severe situations. People with allergies or pre-existing conditions may develop severe reactions, including anaphylaxis, so the Health assessment is recommended in all cases.
When we have been stung by a spider fish, the main thing we have to do is act quickly and in an orderly manner:
- get out of the water and place yourself in a safe place to avoid further contact and the risk of drowning.
- Gently wash the wound with seawater or saline solution. (avoid fresh water initially if possible, as it can promote the release of toxins through osmotic action).
- Remove visible thorns with clean tweezers, without squeezing the wound or trying to squeeze it. If they are not visible, it is preferable to have them removed by medical personnel using appropriate equipment.
- Apply heat: immerse the area in hot water 40–45 ºC (or the maximum tolerable temperature without burning the skin) during 30–90 minutes, renewing the water if it cools. Heat helps denature the poison and reduces pain.
- Pain control: Standard analgesics (e.g., paracetamol or ibuprofen) can be used if there are no contraindications. In medical settings, stronger analgesics or local anesthetics may be used.
- Monitor for signs of severity (respiratory distress, severe dizziness, persistent vomiting, fever, widespread edema, marked pallor or cyanosis). In these cases, seek immediate medical attention.
- Medical check: : it is advisable to have a professional clean in depth, assess the need for antibiotics in cases of risk, and update the tetanus vaccination if appropriate. The wound should not be routinely sutured.
When we have been bitten by a spider fish, the main thing we have to do is:
- Clean and disinfect the wound (preferably with saline solution or seawater; avoid excessive friction).
- Manually remove the thorns that are visible with sterilized tweezers.
- Apply heat to the affected area, by immersing it in hot water at a temperature below 45°C for 30 minutes (ideally up to 90 minutes), to reduce pain.
- Avoid placing cold on the woundAlthough some defend this method, the poison is heat-labile and cold does not inactivate it.
- Avoid applying tourniquets, incisions, oral suction and commercial vacuum devices, which have not proven effective and may worsen the injury.
- Go to an emergency center to receive medical attention and rule out complications.
Explanatory video: https://www.youtube.com/watch?v=0GMJ34LzrJM
Generally, after proper handling, the pain gradually subsides and the swelling reduces in the following hours. However, the patient's progress should be monitored over the following days for signs of infection (increasing erythema, local warmth, discharge) or systemic symptoms. For people with occupational or frequent exposure (fishermen, beach workers, divers), first aid training and access to controlled heat sources at first-aid stations make a significant difference in the prognosis.
Although it is a discreetly camouflaged and elusive fish, knowing its habitat, warning signs and action protocol When stung, you can enjoy the sea safely. Identifying the dorsal fins, understanding their burrowing pattern, and applying heat immediately after a puncture significantly reduces pain and the risk of complications.