The Goliath Tigerfish, Hydrocynus goliath, is a ferocious predatory fish native to the Congo River Basin in Africa. It can grow up to 1.5 meters long and has be known to prey on small crocodiles and tearing large catfish into pieces! It occasionally attacks human since it is able to sense low frequency vibration in the water. It prefers to hunt in fast flowing water where smaller fish struggle to swim. Its massive teeth perfectly slide into distinct patches along its jaw. The Goliath Tigerfish is very rarely kept in any sort of aquarium although I did manage to spot a few at the Singapore River Safari the other day! See video below 🙂
The Calabar Python, Calabaria reinhardtii, is probably one of the most toughest snakes on the planet. Its skin is more than 15 times thicker than an average snake. Scientists believe that this thick layer of skin protects the snake from bites by mother rodents protecting their young. The Calabar Python preys exclusively on young rodents, hence the need to protect itself from protective mothers. Despite the thickness of the skin, it remains flexible. Pharmaceutical companies have shown interest in mimicking the qualities of the snakes skin to develop puncture-resistant medical gloves! The Calabar Python does have some limitations. It cannot swallow large prey like other snakes normally do. This partly explains their preference for small rodents. It also has a very small clutch size for a snake laying an average of 4 eggs per clutch. Other snakes normally lay up to 100 eggs per clutch 😊
Illustration and data retrieved from Mongabay Newsletter “The toughest snake on Earth lives in Central Africa and eats baby rodents”
Predatory fish are awesome in their own right, but are obviously not well-suited for a community tank setup. Here are several distinguishing features that predatory have. None of these features alone would identify a predator, but a combination of them is a worrying sign 😉
Size: Fish that are two or three times bigger than other tank mates might view others as food.
Torpedo body: Long arrow-shaped bodies are designed for sudden bursts of speed to catch prey. Pike and gars are good examples.
Teeth: This may sound obvious, but fish with long obvious teeth designed for grabbing and holding are bound to eat anything that fits in its mouth.
Whiskers: Species of catfish have long elongated whiskers for detecting prey in dark deep waters. Expect them to munch on any type of fish that gets detected with these whiskers.
Camouflage and hiding: Although some peaceful species use camouflage to avoid predation, some use it to hunt! Fish that burry themselves or blend in well with leaves prepare themselves for a surprising attack.
Eye position: Fish with forward facing eyes give them overlapping vision and in-depth perception for ambushing prey.
Pike (Esox lucius)
This could quite possibly be your worst nightmare!
Lamprey’s are a species of prehistoric jawless fish that latch onto other fish to suck blood. Lamprey’s have been around for over 300 million years. They are boneless fish without any scales. Despite the lack of jaws, they are able to suck blood by first using their circular rows of sharp teeth to grab onto the body of the fish. Lamprey’s then carve a hole into the fish with their “tongue” which is lined with sharp teeth as well :O! It then proceeds to suck the fishes blood. The victim fish usually does not die, but the open wound left at end can get infected which could indirectly lead to death. Some juvenile species of lamprey spend their first years of their life filter feeding in fine sediment of river mouths. After a few years, they start to undergo a bizarre metamorphosis of a few months where they develop their bodies for blood sucking. They then move to large lakes or oceans to feed on fish and even marine mammals.
Picture was used from Collin Barras (2 November 2015) in an article by the BBC titled “Meet a Lamprey. Your ancestors”
The Electric Eel, electrophorus electricus, is more closely related to catfish than to an eel. It originates from the Amazon and Orinoco river systems where there is plenty of mud and reeds for it to hide in. It is best known for stunning its prey by producing an electric shock up to 860 volt! The Electric Eel uses this electric shock to hunt its prey and it is very successful in doing so. The electric shock is not life threatening to humans as it is only a quick discharge of electricity. However, it can still cause temporary numbing of a part of your body 😉
In the aquarium, the Electric Eel should only be kept by specialists as this species can easily grow up to two meters. It is not very active so an aquarium 2 to 3 times its body length should be enough. Important is to cover the aquarium as the Electric Eel can easily jump or force its way out. However, do let sufficient air through as the Electric Eel needs oxygen to survive. It will gulp for air every 10 minutes or so. Live or dead feeder fish and worms that are able to fit in its mouth will satisfy the Electric Eel’s dietary requirements.
The Giant Snakehead, channa micropeltes, is one of the largest snakehead species. Lengths over 1 meter are regularly encountered. They are found throughout South-East Asia and have been introduced elsewhere in the world where they are considered an invasive species. Giants Snakeheads are highly adaptable and have the ability to crawl onto land and breath air in muddy conditions. They possess a primitive lung, located behind the gills, which it uses to gulp air. It can therefore travel short distances over land!
These fish are ferocious predators and will chase down anything that will fit in their mouth. They have very sharp teeth that can rip fish into half. It should therefore only be kept in aquaria with similar sized fish, but even then it is risky. Despite its aggressive nature, it is a very beautiful fish with juveniles having distinctive bright lines across their body. As the fish grows older they develop a pattern comprising a broad, dark longitudinal stripe. Adults will defend their brood at all costs and have occasionally injured humans.