Few fish capture the imagination like the Dragon Fish, also known as Polypteridae or Bichir. With their eel-like bodies covered in bony scales, segmented dorsal fins, and a mouth that denotes their predatory nature, these fish look like they’ve come straight out of the dinosaur era. Evolutionarily speaking, they are true living fossils, carrying ancestral traits that make them unique in the world of aquariums. By popular demand, today we delve into the fascinating universe of African Dragon Fish.
Beyond their prehistoric appearance, Polypteridae are intelligent, curious animals with very particular behavior. Originating from the waters of Africa, they are efficient predators and masters of stealth. However, they are not fish for just any aquarium. Their size, specific needs, and notorious ability to escape make them tenants that require serious commitment. In this comprehensive guide, we will unveil all the secrets of Dragon Fish: from their diverse species to their demanding aquarium requirements, feeding, compatibility, and some curiosities that will leave you amazed.
Ancient Inhabitants of Africa: Natural Habitat of the Polypteridae
Dragon Fish are endemic to various regions of Africa. They prefer the calm, shallow waters of rivers, lakes, and swamps, where currents are minimal. They are often found in areas with dense submerged vegetation, fallen logs, and abundant refuges. Although they adapt to different water conditions, they usually inhabit tropical environments, which defines their temperature requirements in the aquarium.
Prehistoric Morphology: A Body Designed for Survival
The physical form of Polypteridae is their most distinctive feature. They are fish with an elongated, cylindrical, and eel-like body, covered by an armor of thick bony scales (ganoid) that provide them with formidable protection. Their head is robust, with a prominent mouth and a strong jaw, clearly indicating their carnivorous diet.
The most striking feature is their dorsal fin, which is not a single continuous fin, but a series of small segmented fins (pinnules), which can vary in number depending on the species. They possess fleshy pectoral fins, similar to small “arms,” which allow them to move along the bottom in a unique way. Reaching an adult size of around 40 cm (although some species can be much larger), they are imposing fish that demand a spacious aquarium.
A World of Varieties: The Most Common and Rare Species
There are numerous species of Polypteridae, each with its own peculiarities, although their general care is similar.
- Polypterus senegalus (Senegal Bichir/Dragon Fish): This is the most common and economical species in the trade. It is an excellent entry point for aquarists interested in these fish. They are usually silvery or grayish in color, and albino and “platinum” (very pure silver color) varieties exist.
- Polypterus ornatipinnis (Ornate Bichir): One of the most impressive species, with a pattern of dark spots and bands on a light background, and yellow or orange fins. It is harder to find and more expensive.
- Polypterus delhezi (Barred Bichir): Recognizable by its dark vertical bands on the body.
- Polypterus weeksii, Polypterus palmas, Polypterus bichir (with various subspecies): Other less common but equally fascinating species, some of which can exceed 60 cm (24 inches) in length.
Most specimens in stores are usually P. senegalus, with other species being more specialized and often available only by special order.
Creating the Dragon’s Realm: Water Parameters and Aquarium
For these prehistoric fish, a suitable environment is vital for their longevity.
Water Parameters
- Temperature: They require tropical temperatures, between 23°C and 28°C (73°F – 82°F).
- pH: They prefer slightly acidic to neutral water, with a pH between 6.5 and 7.5.
- Hardness: They tolerate a wide range, but prefer soft to moderately hard water.
- Nitrates/Nitrites/Ammonia: As large fish with a high bioload, it is essential to keep ammonia and nitrites at zero and nitrates below 20 ppm with regular water changes and a powerful filtration system.
Minimum Aquarium Size
Given that they reach 40 cm (and even more), a minimum aquarium of 400-500 liters (100-130 gallons) is indispensable for a single adult P. senegalus. To keep a group or larger species, a significantly larger tank will be needed. The length of the aquarium is more important than the height, as they are benthic fish and need space to move along the bottom.
Decoration and Environment
- Substrate: They adapt to sand or fine gravel. Avoid very coarse substrates that can trap food and dirty the aquarium.
- Hiding Spots: These are essential. Provide caves, hollow logs, large rocks, and sturdy plants where they can hide and rest. They like to feel safe and protected.
- Lighting: They do not like very strong light. Dim lighting is preferable, and floating plants can help mitigate excessive light, creating shaded areas.
- Current: They prefer calm waters, so the filter current should be moderate.
Community of Giants: Compatibility with Other Fish
Polypteridae have poor eyesight and rely heavily on their sense of smell. They are opportunistic predators, not aggressive.
- Golden Rule: Any fish that fits in their mouth will be considered food.
- Compatible: They should live with fish of similar or larger size, or with fish that are too large or tall to be swallowed. Good companions include other Polypteridae of similar size (avoiding large size differences due to cannibalism), large catfish (Synodontis, Plecos, large Corydoras), medium-sized and peaceful cichlids (some Geophagus or Heros), and other large fish with a calm temperament.
- Incompatible: Small fish like Neon Tetras, Guppies, small Tetras, Rasboras, etc. Very aggressive and fast cichlids that might stress them or steal their food should also be avoided.
The Predator’s Diet: Feeding
Dragon Fish are carnivorous. Although most captive-bred specimens will accept a varied diet, it is important to offer them protein-rich food.
- Dry foods: High-quality granules and sticks for carnivorous fish are a good base. Make sure the food size is appropriate for their mouth.
- Frozen food: This is highly appreciated. Bloodworms, brine shrimp, shrimp, mussels, squid, pieces of white fish (hake) are excellent options.
- Live food: Although not strictly necessary, occasionally offering live food (earthworms, small feeder shrimp) can stimulate their natural hunting behavior. Avoid feeding them live fish from stores, as they can introduce diseases.
They are slow eaters. If you have faster fish, make sure your Polypteridae receive their food, perhaps by feeding them after lights out or directing food to their area.
The Secret to Longevity: Lifespan and Reproduction
Polypteridae are very long-lived fish, with a lifespan exceeding 10 years in captivity, and it’s not uncommon for them to live 12-14 years if provided with adequate conditions.
Reproduction in an aquarium is extremely difficult and rare. Most specimens in trade are captive-bred, but not by home aquarists. Males and females are difficult to differentiate (females are usually a bit more robust). They are substrate or vegetation spawners, and the eggs are adhesive. They require very specific conditions and often a dedicated breeding tank.
Polypteridae Curiosities: An Escape Artist with Gills and Lungs
- Air Breathing: One of their most fascinating abilities. In addition to their gills, they possess primitive lungs (modified bilobed swim bladders) that allow them to breathe atmospheric air directly from the surface. You’ll see them regularly rise to “take a gulp” of air.
- Master Escape Artists: Warning! Polypteridae are tremendous escape artists. Their eel-like bodies and ability to breathe air allow them to slip through incredibly small crevices. They can survive out of water for several hours (not days), as long as their skin remains moist. Therefore, your aquarium must be perfectly covered, without any gaps through which they can escape. If you find one outside the aquarium within an hour or two, you can carefully return it using a damp cloth to avoid damaging its skin. It will recover, but if it dehydrates too much, the damage will be irreversible.
- Poor Vision and Keen Sense of Smell: Their reliance on smell for hunting and orientation, coupled with their limited vision, contributes to their stalking behavior and to not bothering fish too large to be their prey.
The Dragon Fish or Polypteridae is a unique and captivating addition to the right aquarium. Its prehistoric appearance, intelligence, and fascinating behavior make it a rewarding experience for the experienced aquarist looking for a long-term project. They require a significant commitment in terms of aquarium size, water quality, and choice of tank mates, but the reward is observing a creature that has walked (or rather, swum) the Earth for millions of years, adapting and surviving with unwavering elegance. If you are ready for the challenge, a Dragon Fish will offer years of awe and admiration.
FAQs
Why does my Dragon Fish go to the surface and gulp air?
It’s completely normal. They are using their lung-like organ (modified swim bladder) to breathe atmospheric air. It’s a natural adaptation for living in low-oxygen waters and does not indicate a problem, unless they do it excessively.
How big can a Polypterus senegalus get?
Polypterus senegalus typically reaches between 30 and 40 cm (12-16 inches) in a suitable aquarium. Some larger species, like P. bichir, can exceed 60 cm (24 inches).
Can I keep several Dragon Fish together?
Yes, it is possible to keep a group of Polypteridae, especially if they are of similar size to prevent cannibalism. You will need an even larger aquarium and plenty of hiding spots for each to establish its space.
What should I do if my Dragon Fish escapes the aquarium?
First, make sure the aquarium is well-covered to prevent future escapes. If you find it on the floor shortly after it escaped, carefully pick it up using a damp cloth (to protect its skin and yours) and return it to the aquarium. Monitor its recovery; if it’s very dry or has been out for too long, it may not survive.
Is it an aggressive fish or will it bite other fish?
It is not aggressive in the territorial sense. It is an opportunistic predator. If a fish fits in its mouth, it will eat it. It will not bite or harass fish that are too large to be its prey. Its “aggression” is solely linked to feeding.
