🐟 Rock-Bacu – (Lithodoras dorsalis) – Giant Armored South American Catfish

The Rock-Bacu (Lithodoras dorsalis) is a massive and unusual armored catfish native to South America. Belonging to the Doradidae family, this impressive species develops a heavily armored body covered with bony plates, a broad head, powerful build, and unmistakable prehistoric appearance.

Unlike many large predatory catfish, the Rock-Bacu has a fascinating natural diet that includes fruits and aquatic vegetation, particularly during seasonal flooding. In its native habitat, it can even play a role in dispersing seeds after consuming fallen fruit.

Reaching approximately 39 inches (100 cm) in total length, this is an exceptionally large species intended only for aquarists who can provide a massive aquarium, indoor pond, or other appropriately sized permanent enclosure.

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🔎 Quick Facts – Rock-Bacu

• 📛 Common Name: Rock-Bacu, Bacu, Bacu de Pedra
• 🔬 Scientific Name: Lithodoras dorsalis
• 🐟 Family: Doradidae
• 🌍 Origin: South America
• 🌊 Distribution: Amazon River basin and surrounding regions
• 💧 Water Type: Freshwater
• 📏 Maximum Documented Size: Approximately 39 inches / 100 cm
• 🏠 Recommended Aquarium: 500+ gallons for a mature specimen, with larger accommodations preferred
• 🌡️ Temperature: Approximately 75–82°F
• 💧 pH: Approximately 6.0–7.5
• 🍽️ Diet: Omnivorous with strong herbivorous/frugivorous tendencies
• 😇 Temperament: Generally peaceful for its size
• 🐟 Tankmates: Large, robust species only
• ⭐ Care Level: Advanced
• 🛡️ Special Feature: Heavily armored body covered with protective bony plates

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🛡️ Heavily Armored South American Giant

The Rock-Bacu is a member of the thorny catfish family Doradidae.

Its elongated body is largely protected by heavy bony plates that give the fish its distinctive armored appearance.

Adults become extremely thick-bodied and powerful, making this one of the most impressive large South American catfish available to serious aquarium collectors.

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🎨 Appearance

The Rock-Bacu develops:

• A long, heavily built body
• Dark brown to gray coloration
• Thick bony armor plates
• Broad head
• Small eyes
• Three pairs of barbels
• Powerful tail
• Rugged, prehistoric appearance

Coloration can vary between individual fish and may change somewhat depending on age, substrate, lighting, and environment.

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📏 Adult Size

The Rock-Bacu is a true giant.

A maximum length of approximately:

39 INCHES / 100 CM

has been documented.

Because of its enormous adult size and heavy body mass, this species should only be purchased by aquarists who already understand the long-term housing requirements of giant freshwater fish.

Do not purchase a juvenile assuming it will remain small.

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🏠 Aquarium Size

For a mature Rock-Bacu, we recommend planning for:

500+ GALLONS

with even larger accommodations preferred whenever possible.

Large adults may ultimately be better suited to:

• Custom-built aquariums
• Indoor ponds
• Large tropical fish systems
• Public aquarium-style displays

Floor space is extremely important.

The fish should be able to:

• Turn around comfortably
• Rest without contacting aquarium walls
• Swim freely
• Access food easily
• Grow without becoming physically restricted

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🪵 Aquarium Setup

A Rock-Bacu aquarium should prioritize space, safety, and stability rather than excessive decoration.

Recommended setup:

• Sand or smooth substrate
• Large pieces of securely positioned driftwood
• Rounded rocks
• Large open swimming areas
• Strong filtration
• Moderate water movement
• Secure aquarium cover

Avoid sharp decorations that could injure the fish.

Any large décor should be extremely stable because a powerful adult can easily move lightweight objects.

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💧 Water Parameters

A practical aquarium range is:

• 🌡️ Temperature: Approximately 75–82°F
• 💧 pH: Approximately 6.0–7.5
• ☠️ Ammonia: 0 ppm
• ☠️ Nitrite: 0 ppm
• 🔄 Nitrate: Keep controlled through routine water changes

Stable water quality is more important than constantly attempting to achieve one exact pH value.

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💩 Filtration & Water Quality

A giant catfish produces a substantial amount of waste.

Use powerful biological and mechanical filtration appropriate for the aquarium volume and biomass of the fish.

Regular maintenance should include:

• Large routine water changes
• Removal of uneaten food
• Substrate cleaning
• Filter maintenance
• Monitoring ammonia and nitrite
• Controlling nitrate accumulation

Oversized filtration is strongly recommended.

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🍽️ Diet

One of the most interesting characteristics of the Rock-Bacu is its natural diet.

In flooded forests and river systems, this species is known to consume:

• Fruits
• Seeds
• Aquatic vegetation
• Plant material
• Other available organic foods

In captivity, provide a varied diet that may include:

• Quality sinking pellets
• Algae or herbivore wafers
• Appropriate vegetables
• Plant-based foods
• Occasional suitable protein foods
• Other foods formulated for large omnivorous catfish

A varied diet is preferable to feeding primarily high-protein foods.

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🌳 Natural Fruit & Seed Eater

Rock-Bacu are particularly interesting because of their ecological relationship with flooded forests.

During seasonal flooding, they consume fruits and seeds that fall into the water.

After feeding, these fish can help transport and disperse seeds through the river system.

This natural behavior makes the Rock-Bacu very different from the primarily carnivorous diet associated with many other giant catfish.

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😇 Behavior & Temperament

Despite its enormous adult size, the Rock-Bacu is generally considered relatively peaceful.

However, size alone creates important compatibility concerns.

A very large fish can:

• Accidentally injure smaller tankmates
• Outcompete other fish for food
• Move aquarium decorations
• Produce extremely heavy waste
• Consume very small fish opportunistically

Tankmates should therefore be chosen carefully.

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🐟 Tankmates

Potential tankmates should be:

• Large
• Robust
• Peaceful to moderately assertive
• Too large to be swallowed
• Appropriate for similar water conditions

Avoid:

• Small community fish
• Very delicate species
• Highly aggressive fish that may attack the Rock-Bacu
• Fish requiring substantially different water conditions

Even with appropriate tankmates, an aquarium large enough to accommodate all adult fish is essential.

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🥚 Breeding

Breeding Rock-Bacu in home aquariums is extremely uncommon.

In nature, reproduction is associated with seasonal river and floodplain conditions.

Because adults become extremely large and their breeding behavior is tied to natural environmental cycles, successful captive breeding would require specialized facilities well beyond the typical home aquarium.

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⭐ Who Should Keep a Rock-Bacu?

This species is best suited for experienced aquarists who:

• Keep giant freshwater fish
• Have access to extremely large aquariums or indoor ponds
• Understand heavy filtration requirements
• Can provide long-term permanent housing
• Enjoy unusual South American catfish
• Are prepared for a fish approaching 3½ feet in length

This species is not suitable for a standard home aquarium.

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📦 Live Fish Shipping

Rock-Bacu may be shipped via UPS Next Day Air or approved airline cargo, depending on the size of the fish, destination, weather conditions, and current shipping eligibility.

Very large specimens may require airline cargo due to box size, fish size, water weight, and safe transportation requirements.

Shipping is not included in the listed fish price unless specifically stated otherwise.

Please review our current:

• Shipping & Payment Information
• Live Arrival Guarantee
• DOA Policy
• Terms & Conditions

before placing an order.

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🛡️ Important Buyer Information

Please research this species thoroughly before purchasing.

The Rock-Bacu can reach approximately 39 inches and requires an exceptionally large permanent enclosure.

Buyers are responsible for providing:

• Proper long-term aquarium size
• Heavy-duty filtration
• Appropriate water quality
• Suitable diet
• Safe tankmates
• Secure housing
• Any permits or legal requirements applicable to their location

Individual fish may naturally vary in coloration, pattern, body shape, size, and behavior.

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✨ Why Keep a Rock-Bacu?

The Rock-Bacu combines:

• Massive adult size
• Heavy natural armor
• Peaceful behavior for a giant catfish
• Fascinating fruit- and seed-eating habits
• Prehistoric appearance
• True South American river-fish presence

For the properly equipped keeper, Lithodoras dorsalis is an extraordinary centerpiece species and one of the most impressive armored catfish in the freshwater aquarium hobby.