As a passionate tropical freshwater fish follower, I’ve always been drawn to the majestic presence of large fish in aquariums. There’s something captivating about watching these impressive creatures glide through the water, adding a sense of wonder and awe to any home or office space. But before we dive into the best large fish for your tank, let’s take a moment to consider why these aquatic giants are so appealing and what you need to think about before bringing them home.

The Appeal of Large Fish for Fish Tanks

Large fish bring a unique charm to the aquarium hobby. They often have more personality than their smaller counterparts, displaying intelligent behaviors and even recognizing their owners- my wife swears they do! Their size makes them natural focal points in any room, turning your aquarium into a living piece of art. Plus, caring for these magnificent creatures can be an incredibly rewarding experience for any dedicated aquarist.

Considerations before choosing large fish

Before you rush out to buy a big fish, there are a few critical factors to consider. First and foremost is tank size – large fish need ample space to swim, grow, and thrive. You’ll also need to think about filtration systems, water quality management, and the potential need for specialized diets. It’s crucial to research each species thoroughly and ensure you can provide the right environment for your chosen fish to flourish.

Top 5 Large Fish for Fish Tanks

1. Oscar (Astronotus ocellatus)

• Characteristics and personality– Oscars are among my favorite large aquarium fish, and for good reason. These South American cichlids are not only visually striking with their bold patterns and colors, but they’re also known for their fascinating personalities. I’ve found that Oscars can recognize their owners and even interact with them, sometimes begging for food or attention.
• Adult size: 10-12 inches Minimum tank size: 75 gallons for a single Oscar
• Care requirements– Oscars are relatively hardy fish, but they do have some specific needs. They’re messy eaters and produce a lot of waste, so a robust filtration system is essential. I recommend a varied diet of high-quality pellets, supplemented with live or frozen foods like earthworms or crickets. Regular water changes are crucial to maintain good water quality.
• Tankmates– One thing to keep in mind is that Oscars can be territorial and may not play well with smaller fish. If you’re planning to keep Oscars, it’s best to house them with other large, peaceful species or in a species-only tank. These things will eat most smaller fish.

2. Angelfish (Pterophyllum scalare)

• Unique appearance and behavior– Angelfish are a classic choice for large community tanks, and it’s easy to see why. Their distinctive triangular shape and graceful fins make them a visual delight. While not as large as some other fish on this list, they can still reach an impressive size, especially when you consider their tall, sail-like fins.
• Adult size: 6-8 inches tall (including fins), 6 inches long Minimum tank size: 30 gallons for a pair, larger for groups
• Tank setup and maintenance– In my experience, Angelfish thrive in well-planted tanks with plenty of vertical space. They appreciate having some hiding spots, like tall plants or driftwood. While they’re generally peaceful, they can be fin-nippers, so avoid keeping them with long-finned fish like bettas or guppies.
• Angelfish– relatively easy to care for, but they do best in soft, slightly acidic water. I’ve found that a varied diet of quality flakes, frozen foods, and occasional live treats keeps them healthy and brings out their best colors.

3. Discus (Symphysodon spp.)

• The “king of the aquarium”– Often referred to as the “king of the aquarium,” Discus fish are truly a sight to behold. Their circular, disc-shaped bodies come in a stunning array of colors and patterns. While they can be challenging to care for, the reward of successfully keeping these beautiful fish is well worth the effort.
• Adult size: 6-8 inches Minimum tank size: 55 gallons for a small group, larger is better
• Specialized care needs– Discus are known for being somewhat demanding in terms of water quality and care. They prefer soft, acidic water and are sensitive to changes in water parameters. In my experience, frequent water changes and meticulous tank maintenance are key to keeping Discus healthy.
• These fish are schooling by nature– so I always recommend keeping them in groups of at least 5-6 individuals. They thrive on a varied diet, including high-quality flakes, frozen foods, and live foods like bloodworms or brine shrimp.

4. Silver Arowana (Osteoglossum bicirrhosum)

• Prehistoric charm and intelligence– Silver Arowanas are truly impressive fish, with their elongated bodies and prehistoric appearance. These fish are known for their intelligence and have been observed “jumping” to catch prey in the wild. Keeping an Arowana can be like having a living dinosaur in your aquarium!
• Adult size: Up to 3 feet Minimum tank size: 250 gallons or larger
• Specific tank requirements– Arowanas are not for the faint of heart or those with limited space. These fish grow quickly and require massive tanks to accommodate their size and active swimming behavior. In my experience, a long, wide tank with a tight-fitting lid is essential, as Arowanas are known jumpers.
• These fish are predators by nature– they require a diet high in protein. I’ve had success feeding them a combination of large pellets, frozen fish, and occasionally live fish (though this should be done sparingly and responsibly).

5. Red Tail Catfish (Phractocephalus hemioliopterus)

• Impressive size and appearance– Last but certainly not least on my list is the Red Tail Catfish. These gentle giants can grow to enormous sizes, with their distinctive red tail fins and wide, flat heads making them a true showstopper in any aquarium.
• Adult size: Up to 4 feet or more Minimum tank size: 1000 gallons or larger (public aquarium size)
• Challenges of keeping a monster fish– I’ll be honest – keeping a Red Tail Catfish is not for everyone. These fish grow rapidly and can quickly outgrow even large home aquariums. They’re best suited for public aquariums or extremely dedicated hobbyists with the space and resources to provide a suitable environment.
• Red Tail Catfish are omnivorous– will eat almost anything that fits in their mouths. In captivity, they should be fed a varied diet of large pellets, chunks of fish, and occasional treats like earthworms or crayfish.

Keeping large fish in aquariums can be an incredibly rewarding experience for the dedicated fish follower. From the personable Oscar to the majestic Discus, each of these species brings its own unique charm and challenges to the hobby. Remember, with great size comes great responsibility – always research thoroughly and ensure you can provide the appropriate care before bringing any of these magnificent creatures home.

Whether you’re drawn to the interactive personality of an Oscar, the graceful beauty of Angelfish, the regal presence of Discus, the prehistoric allure of Arowanas, or the awe-inspiring size of Red Tail Catfish, there’s a large fish out there to capture your imagination and become the centerpiece of your aquatic world.

FAQs

1. How often should I feed large fish in my aquarium? Most large fish should be fed once or twice a day, offering only as much food as they can consume in a few minutes. Always follow species-specific feeding guidelines.
2. Can I keep different species of large fish together? It depends on the species and their individual temperaments. Some large fish can coexist peacefully, while others may be aggressive or territorial. Research compatibility before mixing species.
3. How can I maintain good water quality in a tank with large fish? Regular water changes, a robust filtration system, and avoiding overfeeding are key to maintaining water quality. Large fish produce more waste, so more frequent maintenance may be necessary.
4. Are large fish suitable for beginners? Some large fish, like Angelfish, can be suitable for intermediate aquarists. However, many large species require advanced care and are better suited for experienced hobbyists.
5. How can I tell if my tank is big enough for a large fish? Research the adult size and specific needs of your chosen species. As a general rule, the tank should be at least 4-6 times the length of the adult fish, with appropriate width and depth for the species’ behavior.