Arapaima In Aquarium – A Realistic Guide To Keeping
Have you ever stood mesmerized in front of a public aquarium, watching a colossal arapaima glide by like a living torpedo? It’s a breathtaking sight. That ancient, armor-plated fish sparks a question in the heart of many ambitious aquarists: “Could I actually keep an arapaima in aquarium at home?”
We get it. The allure of housing a true river monster is powerful. But here at Aquifarm, we believe in responsible fishkeeping first. We promise to give you the complete, unvarnished truth about what it takes to care for this magnificent giant. It’s a journey that goes far beyond a big tank—it requires immense resources, planning, and a deep commitment.
In this ultimate arapaima in aquarium guide, we’ll dive deep into the staggering tank requirements, the demanding diet, the potential for tank mates, and the most common problems you’ll face. We will also explore the critical importance of sustainability, so you can understand the full picture. Let’s explore the world of the arapaima together.
The Giant in the Room: Understanding the Arapaima (Arapaima gigas)
Before we even talk about tanks and filters, let’s appreciate the creature we’re discussing. The arapaima is a true relic, a living dinosaur from the Amazon River basin. These are not just large fish; they are among the largest freshwater fish on the planet.
In the wild, they can reach lengths of over 10 feet and weigh more than 400 pounds. Think about that for a moment. That’s longer than a king-size bed and heavier than a refrigerator. Their scales are so tough they can withstand piranha attacks, and they have a fascinating adaptation: they are obligate air-breathers.
This means they must surface to gulp air using a modified swim bladder that functions like a lung. This ability allows them to thrive in oxygen-poor waters, but it also means they need ample open surface area in any enclosure. Understanding this primal nature is the first step in realizing the sheer scale of their needs.
Your Unimaginable Arapaima in Aquarium: Tank Requirements
This is where dreams meet reality, and it’s the most critical part of our guide. When we talk about tank size for an arapaima, we are not talking about the large tanks you see at your local fish store. We are talking about custom-built, swimming-pool-sized enclosures.
Minimum Tank Size: Think in Thousands, Not Hundreds
Let’s be perfectly clear: a juvenile arapaima might start small, but it will grow incredibly fast—up to a foot in its first year. A “grow-out” tank is not a practical strategy unless you already have its permanent home built and waiting.
For a single adult arapaima, the absolute bare-bones minimum is a tank of at least 2,500 gallons. However, to truly provide a comfortable and ethical habitat, you should be planning for something in the range of 5,000 to 10,000 gallons or more. The tank’s footprint (length and width) is far more important than its height, as these fish need horizontal swimming space.
- Length: At least 4-5 times the fish’s expected adult length. So, for an 8-foot fish, you need a 32-40 foot long tank.
- Width: At least 1.5-2 times the fish’s adult length. For an 8-foot fish, that’s a 12-16 foot width.
This is not an aquarium; it’s an indoor pond. Failing to provide this space is one of the most common problems with arapaima in aquarium care, leading to stunted growth, spinal deformities, and a drastically shortened lifespan.
Filtration and Heating: Industrial-Grade Solutions
A fish this large produces an enormous amount of waste. Your standard canister or hang-on-back filter won’t even make a dent. You need a filtration system designed for a large pond.
This typically involves:
- Massive Sump Systems: A large, external sump (hundreds of gallons itself) filled with high-quality biological and mechanical media.
- External Pond Filters: Pressurized bead filters or large bog filters are often necessary to handle the biological load.
- High-Flow Pumps: You’ll need powerful pumps to circulate thousands of gallons of water per hour.
Heaters must also be heavy-duty and, most importantly, shatterproof and protected. A large, startled arapaima can easily break a glass heater, which could be catastrophic. Multiple, high-wattage titanium heaters with external controllers are the safest bet.
Lid and Decor: A Lesson in Security
Arapaima are powerful jumpers. When they come up for air or get spooked, they can launch themselves completely out of the water. A simple glass lid is a recipe for disaster. You need a heavy, custom-built, and securely fastened lid, likely made from reinforced steel or wood framing with strong mesh. There are no second chances here.
As for decor, keep it minimal and unbreakable. Large, smooth driftwood and massive, rounded boulders are options, but anything that can be knocked over or has sharp edges is a hazard. Many of the most successful arapaima enclosures have no substrate at all to make cleaning easier.
Feeding a River Monster: Diet and Nutrition
Figuring out how to arapaima in aquarium feeding works is a major financial and logistical commitment. A growing arapaima has a voracious appetite. As juveniles, they will eat insects, small fish, and crustaceans.
As they grow, their diet must evolve. Here are some of the arapaima in aquarium best practices for feeding:
- High-Quality Carnivore Pellets: This should form the staple of their diet. Look for large-sized pellets formulated for monster fish, like those made for arowana or groupers.
- Whole Foods: Supplement the pellets with whole, market-bought fish (frozen and thawed to kill parasites). Silver-sides, tilapia, smelt, and prawns are excellent choices. Avoid fatty fish like goldfish, which can lead to health problems.
- Feeding Schedule: Juveniles need to eat daily, while adults can be fed every 2-3 days. Do not overfeed, as this will rapidly pollute even the largest of tanks.
The cost of feeding an adult arapaima can easily run into hundreds of dollars per month. This is a significant ongoing expense that must be factored into your budget from day one.
Temperament and Tank Mates: Choosing Companions Wisely
Surprisingly, for a predator of its size, the arapaima is not overly aggressive toward fish it cannot swallow. They tend to be relatively peaceful giants. The key phrase, however, is “fish it cannot swallow.” Anything that can fit in its massive mouth will eventually become a meal.
Choosing tank mates is extremely limited and depends entirely on having a truly colossal tank to give everyone enough space. Suitable companions include:
- Large Catfish: Red-tailed catfish, tiger shovelnose (in the largest of systems).
- Pacu: Both black and red-bellied pacu grow large enough to hold their own.
*Other Giants: In public aquarium settings, they are often kept with other large characins, arowanas, or freshwater stingrays.
Never, ever attempt to keep an arapaima with smaller, community-style fish. Providing good arapaima in aquarium tips means being honest: for 99% of keepers, an arapaima should be the single centerpiece of a species-only system.
The Ethics of Keeping Giants: A Sustainable and Eco-Friendly Approach
This is perhaps the most important section of this entire guide. Arapaima are listed on CITES Appendix II, which means their trade is regulated to prevent over-exploitation. They are a vulnerable species in their native habitat due to overfishing and habitat loss.
If you are even considering this path, embracing a sustainable arapaima in aquarium philosophy is not optional; it’s a moral requirement.
Source Captive-Bred Only
You must only purchase an arapaima that is verifiably captive-bred. Wild-caught specimens contribute to the decline of wild populations and undergo immense stress during transport. Ask for documentation and buy only from highly reputable dealers who specialize in monster fish.
The Rehoming Problem
What happens if you can no longer care for your arapaima? You cannot simply “rehome” a 6-foot, 200-pound fish. Public aquariums and zoos are almost always at capacity and will not take in privately owned animals. This is a lifelong commitment that may even outlive you, as they can live for over 20 years.
An eco-friendly arapaima in aquarium approach means having a plan for the fish’s entire life before you ever bring it home. This is a responsibility you accept for the animal’s entire existence.
Frequently Asked Questions About Keeping an Arapaima
What is the absolute minimum tank size for an arapaima?
While some might say 1000-2000 gallons, we strongly advocate for a minimum of 2,500 gallons for a single adult, with 5,000+ gallons being far more ethical and humane. The tank’s footprint (length and width) is more important than its depth.
How fast do arapaima grow?
Extremely fast. A healthy juvenile can easily grow an inch per month, reaching 2-3 feet in its first couple of years. You cannot keep one in a smaller tank with the plan to upgrade “later.” The permanent, massive enclosure must be ready from the start.
Can I keep an arapaima in a 500-gallon tank?
Absolutely not. A 500-gallon tank might seem huge, but it’s dangerously small for an arapaima. It would be like a human living their entire adult life in a walk-in closet. Keeping one in such a small space will lead to severe health issues, stunting, and a painful, premature death for the fish.
Are arapaima aggressive?
They are predatory but not typically aggressive toward fish they cannot eat. Their aggression is passive; they simply consume anything that fits in their mouth. Their sheer size and power can also cause accidental injuries to other fish in an inadequately sized tank.
A Final Thought on This Living Legend
Keeping an arapaima in aquarium is the Mount Everest of the freshwater hobby. It is a monumental challenge that is reserved for a tiny fraction of the most dedicated, well-funded, and expert aquarists. It’s less about fishkeeping and more about zoo-keeping.
For most of us, the best way to enjoy these magnificent creatures is at a public aquarium, where they have the space and expert care they truly need to thrive. We encourage you to dream big in this hobby, but to always keep responsibly. Your fish, from the smallest guppy to the mightiest giant, depend on your wisdom and foresight.
