How to distinguish a predatory fish

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 ūüėČ

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.

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Pike (Esox lucius)

 

 

 

Lamprey

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.

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Picture was used from Collin Barras (2 November 2015) in an article by the BBC titled “Meet a Lamprey. Your ancestors”

Electric Eel

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 ūüėČ

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.

Breeding Dwarf Snakehead

Dwarf Snakeheads are some of the more colourful snakeheads around and usually grow to a maximum of 20 cm. In order for a pair to breed, the aquarium needs to be bio-tope correct according to the natural requirements of this species.

This species is best bred in a species only aquarium with a breeding pair. Seasons have to be mimicked, so during the winter months the temperature of the aquarium should drop to around 15¬įC and the fish should be fed only when they beg to be fed (maintain this for at least 10 weeks). Then, gradually raise the temperature with regular 50% water changes to mimic the arrival of the rainy season.¬†Dwarf Snakeheads are not too fussy of the water parameters as long as extremes are avoided. Tap-water should be fine.

In the wild Dwarf Snakeheads breed at the end of their winter period, before the majority of the rain comes. Dwarf Snakeheads will breed when the water temperature is around 24-26¬įC. After the eggs are released the male will incubate the eggs in its mouth while the female guards the territory. Incubation period is between 5 to 8 days. Once “hatched”, the fry will be fed by the female that squirts out infertile eggs as food for the fry. It is therefore important to feed the female. After about two weeks, the fry can be given flakes.

Tank set-up:

  • At least 90cm/36in tank
  • Fine sand
  • A fair amount of plants
  • Plenty of hiding places like plastic pipes and hollow logs
  • Floating plants…MUST! This will give shadow and increase activity of the snakeheads
  • Filtration is not necessary as long as you have a substantial amount of plants
IMG20170512223026Dwarf Snakehead species, Channa Bleheri (picture from MP&C Piednor.Aquapress.com)

 

 

Giant Snakehead

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.

IMG_65174Pictures above is thanks to Zooish from Zoochat

Tiger Barb

The Tiger Barb is a beautiful fish that is found in clear or turbid shallow waters of moderately flowing streams. They live in Indonesia and Borneo and their average lifespan is about 6 years. It has four very distinctive black stripes, which resembles the pattern of a tiger. These fish are very active and playful, which makes them fun to watch. They are also fairly hardy and easy to keep provided that frequent water changes regularly occur. The species does need company, and will do best with 6 or more in a group. Having schools of 20+ will make these Tiger Barbs look even more spectacular! DO NOT house these fish with long-finned or slow-moving fish as Tiger Barbs are well known fin-nippers! Gouramis and Anglefish should not be housed together with Tiger Barbs. When Tiger Barbs are kept in larger groups they tend to be less aggressive as they are more busy chasing each other. I personally like to house Tiger Barbs with other fish of Sumatran biotope, such as Bala Shark and Clown Loach.

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Roti Island Snake-necked Turtle

The roti island snake-necked turtle is an oddly shaped freshwater turtle found only on the Indonesian island of Rote. The neck is nearly as long as the carapace of the turtle and is extremely mobile. In the wild it only exists in small isolated pockets in the central highlands of Rote Island. The species is an island endemic and is very susceptible to human interference. The exotic pet trade has decimated this species in the wild as it is one of the most desired turtle in the international pet trade.

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Giant Pangasius

The Giant Pangasius, or Paroon Shark, is a huge fish inhabiting the Mekong River Basin in South East Asia. It can reach an incredible length of 3 metres! It is not a shark, but rather a species of whisker-less catfish. It is a migratory fish and lays its eggs just before the monsoon season. It has a perfectly streamlined body with an elegant dorsal fin. The natural population has declined drastically over the last couple of decades as a result of overfishing. This has made the remaining Giant Pangasius populations severely fragmented and critically endangered.

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Blood Parrot

The blood parrot is an interesting fish with a round balloon-shaped¬†body and a¬†small mouth.¬†Since it’s a hybrid developed by humans it does not occur in the wild. They come in many colours, but the most striking ones are those with yellow or red colour.¬†The blood parrot is very popular aquarium fish. It is a hardy fish and is therefore easy for the beginner¬† They are, however, messy eaters and will only consume part of the food that is given. A powerful filter and good cleaning of the substrate is necessary when keeping these fish. Originating from cichlid parents, one would expect these fish to be aggressive. However, this is far from the case and these fish can easily be housed with similar sized fish such as Angelfish, Corydoras, Silver Dollars and many catfish species.They are called parrotfish because their nose looks like the beak of a parrot ūüôā

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Wels Catfish

The Wels catfish, Silurus glanis,¬†is one of the largest fresh water fish in the world.¬†Accurate measurements¬†over the last couple of decades have shown¬†several specimens of over two metres in length, the longest and heaviest being 2.78m (144kg). It’s a not the most attractive fish you will ever see as it has a long snake-like body, with slimy skin and a huge mouth. Using its¬†long barbels, it tracks its prey by hearing and smelling.¬†The eyesight of a Wels catfish is fairly poor, but it enjoys a tapetum lucidum which gives¬†it reasonable vision at night. They eat insects, crustaceans and other fish. The larger ones go after small mammals and aquatic birds. It is rarely kept in the aquarium due to its sheer size.

This giant fish has been introduced in several European rivers, including the Seine and Po rivers in France and Italy respectively. In some areas, they are known to lunge out of the water to grab pigeons on land. Check youtube for video’s on this! Also the 6th season “cities” of the BBC’s Planet Earth II series spends time covering this phenomena.

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Photo from the Watershed Council Petoskey