12 Large Fish for Freshwater Aquariums

Setting up a freshwater aquarium can be a rewarding experience, but choosing the right fish can be tricky—especially if you’re looking for larger species. Large freshwater fish bring beauty and personality to your tank, but they also come with unique care requirements. As a pet owner, you want to ensure your aquatic friends thrive in their new environment. Let’s explore 12 large freshwater fish that can make a stunning addition to your aquarium and how to care for them properly.

🩺 Vet Recommendations

Before adding any large fish to your aquarium, it’s important to consider their specific needs. Large freshwater fish often require ample space, high-quality water conditions, and a compatible community of tank mates. Some species are more peaceful, while others can be territorial or predatory. Understanding these factors will help you create a healthy and harmonious tank environment.

Here are some key recommendations when keeping large freshwater fish:

• Choose an appropriately sized tank—many large fish need at least 75 gallons or more.
• Maintain stable water parameters, including temperature, pH, and filtration.
• Research compatibility with other fish species to avoid aggression or stress.
• Provide hiding spots, plants, and open swimming areas for enrichment.

With these guidelines in mind, let’s dive into 12 large freshwater fish species you might consider for your aquarium.

📋 Care Tips for 12 Large Freshwater Fish

1. Oscar Fish

Oscar fish are a popular choice for large aquariums. These intelligent, interactive fish can grow up to 12–14 inches. They’re known for their bold personalities but can be territorial, so they’re best kept in a species-specific tank or with other large, non-aggressive fish.

• Tank size: Minimum 75 gallons
• Diet: Carnivorous—feed high-quality pellets, frozen food, and live insects
• Temperament: Semi-aggressive

2. Silver Arowana

The silver arowana is a striking fish with its long, slender body and metallic sheen. They can grow up to 3 feet in length, making them suitable only for very large tanks. Arowanas are surface dwellers and may jump, so a tightly secured lid is essential.

• Tank size: Minimum 250 gallons
• Diet: Carnivorous—requires live or frozen fish, insects, and crustaceans
• Temperament: Predatory

3. Common Pleco

Plecostomus, or plecos, are hardy bottom-dwelling fish that can grow up to 24 inches in length. They’re known for their algae-eating habits but should also be given sinking pellets and vegetables for proper nutrition.

• Tank size: Minimum 100 gallons
• Diet: Herbivorous—algae, sinking wafers, and blanched vegetables
• Temperament: Peaceful

4. Discus

Discus fish are colorful, elegant, and highly sought after by aquarists. They grow to around 8–10 inches and thrive in groups of at least five. These fish require pristine water conditions and are best suited for experienced aquarium keepers.

• Tank size: Minimum 75 gallons
• Diet: Omnivorous—flake food, pellets, and frozen bloodworms
• Temperament: Peaceful

5. Severum

Severums are medium-to-large cichlids with a peaceful demeanor compared to other species in their family. They can grow up to 10 inches and come in various color morphs, including gold and green.

• Tank size: Minimum 55 gallons
• Diet: Omnivorous—vegetable matter, pellets, and frozen food
• Temperament: Peaceful but territorial during breeding

6. Bala Shark

Bala sharks are sleek, silver fish with striking black-tipped fins. Despite their name, they are not true sharks. These active swimmers can reach up to 12 inches in length and thrive in schools of three or more.

• Tank size: Minimum 125 gallons
• Diet: Omnivorous—flakes, pellets, and frozen food
• Temperament: Peaceful

7. Flowerhorn Cichlid

Flowerhorn cichlids are known for their vibrant colors and unique “nuchal hump” on their forehead. They are hardy and grow up to 16 inches, but their aggressive nature means they’re best kept alone or with robust tank mates.

• Tank size: Minimum 75 gallons
• Diet: Omnivorous—specialized pellets, live food, and vegetables
• Temperament: Aggressive

8. Clown Loach

Clown loaches are playful, social fish that thrive in groups of five or more. These bottom-dwellers can grow up to 12 inches and require a spacious tank with hiding spots and soft substrate.

• Tank size: Minimum 100 gallons
• Diet: Omnivorous—sinking pellets, vegetables, and live food
• Temperament: Peaceful

9. Giant Gourami

The giant gourami is a hardy, adaptable fish that can grow up to 28 inches. They are intelligent and can even recognize their owners. However, they may become territorial as they age.

• Tank size: Minimum 200 gallons
• Diet: Omnivorous—vegetables, pellets, and live food
• Temperament: Semi-aggressive

10. Redtail Catfish

Redtail catfish are stunning but require a significant commitment due to their size—they can grow over 4 feet long. These bottom-dwelling predators are best suited for public aquariums or large ponds.

• Tank size: Minimum 500 gallons
• Diet: Carnivorous—live or frozen fish and meat
• Temperament: Predatory

11. Peacock Bass

Peacock bass are large, predatory fish that can grow up to 24 inches. They are known for their striking colors and require a spacious tank with strong filtration.

• Tank size: Minimum 200 gallons
• Diet: Carnivorous—live fish and protein-rich foods
• Temperament: Aggressive

12. Frontosa

Frontosa are beautiful, striped cichlids native to Lake Tanganyika in Africa. They can grow up to 12 inches and prefer living in groups. These fish are relatively peaceful but require stable water conditions.

• Tank size: Minimum 100 gallons
• Diet: Carnivorous—pellets, frozen food, and live food
• Temperament: Peaceful

✅ Do’s and Don’ts

When keeping large freshwater fish, follow these important guidelines:

• Do research each species’ specific care needs before purchasing.
• Do invest in a high-quality filtration system to handle the bioload.
• Don’t overcrowd your tank, as this can lead to stress and disease.
• Don’t mix incompatible species, as this can result in aggression or injury.

💡 Expert Advice

Caring for large freshwater fish can be a rewarding experience, but it requires planning and commitment. Always prioritize your fish’s well-being by providing a spacious, clean, and enriching environment. If you’re unsure about compatibility or care requirements, consult a trusted veterinarian or aquatic specialist for guidance.

FAQs

Q: How do I know if my tank is large enough for big fish?
A: Check the specific tank size requirements for each species. As a general rule, larger fish need at least 75–100 gallons, with some requiring 200 gallons or more.

Q: Can large freshwater fish live together?
A: It depends on the species. Some are peaceful and can coexist, while others are territorial or predatory. Research compatibility before adding fish to your tank.

Book a $49 online vet consultation at https://www.dialavet.com for fast, expert advice.

References

• PetMD
• ASPCA
• VCA Animal Hospitals
• Fishkeeping World
• Dial A Vet – Blog Library