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Setting up a freshwater aquarium is an exciting experience, but for those looking to go beyond common species, exotic fish can add a truly unique touch. These rare and fascinating creatures enhance the beauty and biodiversity of any aquarium, providing a glimpse into the incredible diversity of aquatic life.
For beginners eager to explore rare freshwater species, choosing fish that are both visually striking and manageable in captivity is essential. In this guide, we highlight three of the most exotic freshwater fish available at Anchor Aquarium, along with expert care tips to ensure they thrive in their new environment.
1. Platinum Arapaima (Arapaima gigas) – A True Exotic Freshwater Fish
Why is the Platinum Arapaima So Exotic?
The Platinum Arapaima is an ultra-rare, selectively bred variation of the Arapaima gigas, one of the largest freshwater fish species in the world. Native to the Amazon River Basin, this species is highly sought after for its impressive size, shimmering platinum-white coloration, and prehistoric appearance.
Arapaimas are known as “living fossils”, as they have existed for millions of years. Their bony tongues and ability to breathe air make them unique among freshwater fish. While the standard Arapaima is already a stunning species, the platinum variety is exceptionally rare, making it a true collector’s fish.
Platinum Arapaima Diet
The Platinum Arapaima is a carnivorous fish with a strong preference for protein-rich diets. In the wild, it primarily consumes:
✔ Smaller fish
✔ Crustaceans (shrimp, crabs, and prawns)
✔ Insects and amphibians
In captivity, a well-balanced diet should include:
- Fresh fish fillets (avoid oily fish like salmon, as they can affect water quality).
- Whole shrimp (raw or frozen, shelled for easier digestion).
- High-protein pellets designed for large carnivorous fish.
- Live foods on occasion, such as feeder fish, although not necessary for nutrition.
- Supplemental vitamins to support immune function and scale health.
Feeding Behavior and Considerations
- Juveniles should be fed daily, as they grow rapidly and require consistent nutrition.
- Adults should be fed 3–4 times per week to prevent overfeeding and maintain a healthy metabolism.
- Avoid excessive live feedings, as they can lead to aggressive behavior and nutrient imbalances.
Platinum Arapaima Behavior
Despite its massive size, the Platinum Arapaima is a relatively peaceful fish. It prefers slow-moving waters and spends much of its time near the surface, where it gulps air due to its bimodal breathing system.
Key Behavioral Traits of the Platinum Arapaima
The Platinum Arapaima is a fascinating species not only due to its size and striking appearance but also because of its unique behavioral patterns. Despite being one of the largest freshwater fish in the world, it is known for being generally docile, although its territorial instincts can emerge in smaller enclosures. Understanding its behavior is essential for ensuring a healthy and stress-free environment.
Generally Docile, but Can Become Territorial in Small Tanks
In a spacious environment, the Platinum Arapaima remains calm and non-aggressive, focusing on its natural behaviors such as slow cruising near the surface and occasional bursts of speed when hunting or startled. However, in smaller tanks or enclosed spaces, territorial tendencies may arise. A cramped environment can lead to stress, increased aggression, and potential injuries as the fish struggles to move freely.
To avoid this, it is essential to provide sufficient swimming space and ensure that the tank is not overcrowded with other large species. Even though it is not inherently aggressive, it may unintentionally push or bump into other fish, leading to stress or injury among tank mates.
Best Suited for Large Ponds or Massive Aquariums with Limited Tank Mates
Due to its potential to grow over 8 feet in length, the Platinum Arapaima thrives in expansive aquatic environments. Ideally, they should be kept in indoor ponds, public aquariums, or tanks exceeding 1,000 gallons. These large water volumes allow the fish to exhibit natural behaviors, including surface-breathing, slow gliding, and predatory lunges.
Unlike smaller fish that can adapt to community aquariums, the Arapaima requires careful planning in terms of space and tank mates. Keeping only one or a well-managed pair in an appropriately sized environment is often the best approach.
Slow but Deliberate Swimmer—Needs Plenty of Space to Move Freely
Despite its massive size, the Platinum Arapaima is not a rapid swimmer in most situations. Instead, it moves with graceful, slow motions, conserving energy while navigating its surroundings. However, it is capable of powerful bursts of speed, particularly when startled or when lunging for prey.
This means that the aquarium or pond must provide ample turning space. Sharp corners, excessive decorations, or obstacles can be problematic, as the fish may struggle to maneuver properly. Large, open areas with minimal obstructions ensure that the Arapaima can swim naturally without risk of injury.
Recognizes Owners and Often Interacts During Feeding Time
One of the most fascinating aspects of keeping a Platinum Arapaima is its high level of intelligence and recognition of its caretaker. Unlike many fish that exhibit purely instinctual behavior, the Arapaima can learn to associate people with feeding times. Over time, it may surface when it sees its owner approaching and even show signs of excitement during meal preparation.
Many aquarists report that their Arapaima will follow their movements outside the tank or even allow gentle interactions such as hand-feeding. However, caution should always be exercised, as their powerful jaws and reflexive feeding responses can pose a risk if they mistake fingers for food.
Ideal Tank Mates for the Platinum Arapaima
Since the Platinum Arapaima is a predatory species, selecting appropriate tank mates is crucial. Smaller fish will likely be seen as potential prey, even if they are not actively hunted. The best companions for a Platinum Arapaima include:
- Giant Gouramis – These large, peaceful fish can coexist with Arapaima without triggering aggression.
- Other Large Amazonian Fish – Species such as Pacu, Arowanas, or Peacock Bass can be considered if the tank is large enough.
- Arapaimas of Similar Size – In very large enclosures, keeping multiple Arapaimas can be possible, but they must be introduced at a young age and monitored for compatibility.
It is important to observe interactions regularly to ensure that no signs of stress, dominance, or competition for food develop among the fish.
2. Tigrinus Catfish (Brachyplatystoma tigrinum) – The Striped River Predator
Why is the Tigrinus Catfish Special?
The Tigrinus Catfish, also known as the Tiger Shovelnose Catfish, is one of the most sought-after exotic freshwater species due to its striking black-and-white striped pattern, elongated body, and large whiskers. Native to the Amazon and Orinoco River Basins, this catfish is a true predator, making it a captivating addition to large aquariums.
Tigrinus Catfish Diet
The Tigrinus Catfish is a strict carnivore, and its diet must be high in protein to support its active metabolism. In the wild, it consumes:
✔ Small fish
✔ Aquatic invertebrates
✔ Worms and crustaceans
For captive care, an optimal diet includes:
- Fresh fish fillets (tilapia, whitefish, or similar lean options).
- Frozen prawns and shrimp.
- Live foods on occasion, such as earthworms and mealworms.
- High-quality sinking pellets designed for carnivorous bottom feeders.
Feeding Behavior and Considerations
✔ Juveniles should be fed daily in smaller portions to avoid digestive stress.
✔ Adults should be fed 3–4 times per week with varied protein sources.
✔ Avoid overfeeding, as uneaten food can deteriorate water quality.
Tigrinus Catfish Behavior
Unlike many catfish, the Tigrinus Catfish is more active and free-swimming.
Key Behavioral Traits of the Tigrinus Catfish
Prefers Staying at the Bottom but Will Explore All Levels of the Tank
The Tigrinus Catfish is primarily a bottom-dwelling species, spending most of its time resting on the substrate or slowly moving along the lower regions of the tank. However, unlike some strictly bottom-feeding catfish, it is known to venture into mid and upper levels, especially when searching for food or adjusting to new surroundings. This behavior makes it more interactive and visible compared to other nocturnal bottom dwellers, allowing aquarists to observe its striking black-and-white striped pattern more frequently.
To support its natural habits, the tank should have smooth substrate and minimal sharp decorations to prevent injury, as Tigrinus Catfish have delicate whiskers (barbels) that they use to sense their environment.
Solitary and Territorial—Not Recommended for Small Tanks with Multiple Bottom Dwellers
While not overly aggressive, the Tigrinus Catfish is known to be territorial when it comes to other bottom-dwelling species. In small or overcrowded tanks, it may exhibit defensive behaviors, particularly toward fish that invade its preferred resting spots.
For this reason, it is best kept alone or with mid-to-upper-level fish that will not compete for space at the bottom. If kept with other bottom dwellers, ensure that the aquarium is large enough (250 gallons or more) to allow for separate territories and minimize potential conflicts.
Can Be Skittish if Startled, but Generally Non-Aggressive Towards Similar-Sized Fish
The Tigrinus Catfish is generally a peaceful species, but it can be easily startled by sudden movements or bright lights. In response, it may dart quickly around the tank, potentially injuring itself if the environment is cluttered with sharp decorations. To prevent stress, it is best to:
- Provide dim lighting or floating plants to diffuse bright lights.
- Avoid sudden hand movements or tapping on the glass.
- Ensure the tank has sufficient hiding spots, such as driftwood or caves, where the catfish can retreat if it feels threatened.
Despite being easily startled, it rarely shows aggression toward similarly sized fish, making it a suitable addition to community tanks with large, peaceful species.
Excellent Nocturnal Hunter, Making It an Engaging Species for Night-Time Observation
Being a predatory species, the Tigrinus Catfish is most active at night, using its long whiskers to detect food in low-light conditions. This makes it a highly engaging species for aquarists who enjoy nighttime aquarium observation.
To support its natural hunting behavior:
- Offer food during the evening or nighttime hours, when it is most active.
- Use low-intensity or blue “moonlight” LEDs to create a more natural, dusk-like setting.
- Ensure the aquarium has plenty of space for it to swim and explore freely.
3. Inferno Flowerhorn Hybrid (Cichlasoma sp.) – A Fiery, Colorful Masterpiece
Why is the Inferno Flowerhorn So Unique?
The Inferno Flowerhorn is a hybrid cichlid developed through selective breeding, making it one of the most vibrant and personality-driven exotic fish in the hobby. Unlike wild species, Flowerhorns are artificially created and are famous for their brilliant red, orange, and gold coloration, as well as their large forehead nuchal hump (kok).
Inferno Flowerhorn Diet
The Inferno Flowerhorn is an omnivore, but its diet should be rich in protein to maintain its bright coloration. Recommended foods include:
✔ High-protein cichlid pellets (essential for growth and color enhancement).
✔ Crustaceans (shrimp, krill, and crayfish).
✔ Vegetable matter (blanched spinach, peas, and spirulina-based pellets).
✔ Occasional treats of live or frozen foods like bloodworms.
Feeding Behavior and Considerations
✔ Feed twice daily in controlled portions.
✔ Provide color-enhancing foods (such as astaxanthin-rich pellets) to maintain their vivid hues.
Inferno Flowerhorn Behavior
Highly Territorial—Best Kept Alone or with Other Aggressive Cichlids
The Inferno Flowerhorn is one of the most territorial and aggressive freshwater fish, a trait inherited from its cichlid ancestors. It is highly protective of its space, especially as it matures, often displaying aggressive posturing, flaring its gills, and chasing away any perceived intruders.
Due to its territorial nature, the Flowerhorn is best kept alone unless housed with other large, equally aggressive cichlids in a sufficiently large tank (at least 125 gallons for multiple specimens). Compatible tank mates should be:
- Robust and assertive species like Red Devils, Midas Cichlids, or Jaguar Cichlids.
- Similar-sized cichlids with the ability to defend themselves without excessive fighting.
- No small or passive fish, as they will be harassed or even killed.
To minimize stress, if multiple Flowerhorns or other aggressive fish are kept together, ensure:
- The aquarium is large enough for separate territories.
- There are rock formations or dividers to break lines of sight and reduce conflicts.
- Close monitoring of interactions to prevent excessive aggression.
Intelligent and Interactive—Recognizes Its Owner and Can Be Hand-Fed
Unlike many fish that operate purely on instinct, Flowerhorns are highly intelligent and exhibit interactive behavior similar to that of a pet dog. Over time, they learn to recognize their owner, follow movements outside the tank, and even respond to feeding routines.
Some notable behaviors include:
- Swimming toward the glass when they see their caretaker.
- Begging for food by wagging their fins or flaring their gills.
- Displaying unique personalities, with some being playful and inquisitive, while others may be more dominant and assertive.
Due to their intelligence, Flowerhorns can be trained to take food directly from their owner’s hand. However, caution should be exercised, as their powerful jaws can accidentally bite fingers.
Requires Decorations for Enrichment, Such as Caves and Plants
Despite their aggressive nature, Flowerhorns require a stimulating environment to prevent boredom and stress. Without proper enrichment, they may exhibit:
- Glass surfing (constantly swimming back and forth along the tank walls).
- Digging or moving substrate aggressively.
- Flashing or rubbing against objects due to frustration.
To keep them engaged, include:
✔ Caves or large rocks for territorial security.
✔ Artificial plants (as they tend to uproot real ones).
✔ Floating objects or toys, such as mirrors, to stimulate interaction.
A well-structured environment not only enhances their mental well-being but also encourages their natural displays of dominance and beauty, making them one of the most captivating fish to observe in an aquarium.
Start Your Exotic Aquarium Journey
If you’re looking for truly unique freshwater fish, the Platinum Arapaima, Tigrinus Catfish, and Inferno Flowerhorn are some of the most stunning and rewarding species you can own.
Visit Anchor Aquarium today to find these incredible species and start your journey into exotic aquarium keeping!