I stood in the client's living room last Tuesday. 12-foot ceiling. Marble floors. A 3-meter empty wall. "I want an arowana tank here," he said. "Something impressive." That's when I started asking the questions that actually matter. After specifying 40+ large fish tank projects, I can tell you: the size of the tank isn't decided by the wall. It's decided by the fish. The arowana will grow to 60-90cm. That decides everything else.
The client wanted an "impressive" tank.
That's not a specification. That's a feeling.
My job is to turn that feeling into numbers. Into drawings. Into something the factory can build.
Here's how I do it.
Start With the Fish, Not the Tank
First question: "What kind of arowana?"
That determines everything.
Silver arowana: Grows to 60-90cm. Needs at least 180cm length tank. Asian arowana: Grows to 50-70cm. Needs at least 150cm length tank. Red arowana: Grows to 60-80cm. Needs at least 180cm length tank.
The rule: tank length should be at least 3x the adult fish length.
Why? Because arowanas are big swimmers. They need room to turn. Room to swim.
If the tank is too small? The fish gets stressed. It stops eating. It dies.
Then Size the Tank
Once I know the fish, I size the tank.
For a 90cm adult arowana? That's 270cm tank length minimum.
Width? At least 60cm. The fish needs room to turn. Height? At least 70cm. Arowanas are tall-bodied fish.
So we're looking at a tank around 270 × 70 × 80cm.
That's about 1,500 liters. That's 1,500 kg of water.
Then Check the Room
Now we go back to the room.
Can the wall handle 1,500 kg? That's the next question.
Most residential walls can't. You need structural support. Steel beams. Reinforced concrete.
I've been in rooms where the owner wanted a 2-meter tank on a 1990s plasterboard wall. It would have fallen through the floor.
Then Specify the Filtration
Arowanas are messy. They eat big food. They produce big waste.
You need proper filtration.
For a 1,500-liter arowana tank? Sump filter. At least 200 liters sump volume.
The rule: sump volume should be at least 15% of tank volume.
Protein skimmer? No, that's for saltwater. Freshwater arowana tanks need good mechanical and biological filtration.
Then the Equipment
What else?
- Heater: 2 × 300W (redundant)
- Return pump: 3,000-4,000 GPH
- UV sterilizer: 36W
- LED lighting: 150W (arowanas need a bit of moonlight)
The 40-Project Lesson
I've specified 40+ large fish tank projects.
The clients who start with the fish? They get a tank that works. The fish grows. It's healthy. It's impressive.
The clients who start with the wall? They end up with a tank that's too small. The fish grows too fast. They need a bigger tank in 2 years.
That's the difference.
What I'm Not Going to Tell You
I can tell you how to size the tank. I can tell you what filtration it needs. I can tell you what equipment goes on it.
But I'm not going to tell you which arowana to buy. I'm not going to tell you how to feed it. I'm not going to tell you how to maintain it.
That's the fishkeeper's job.
What We Specify at Ruibit
When we work on a large fish tank project, we start with the fish.
We ask: "What are you keeping? How big will it get?"
Then we size the tank. Then we check the room. Then we spec the filtration.
We don't start with a wall. We start with a fish.
The Living Room
I'm back in that living room.
The client wanted something impressive on that 3-meter wall.
We spec'd a 270cm tank. 1,500 liters. Sump filtration. Structural support.
It's being built now.
When the arowana reaches 90cm, it'll have room to swim. It'll be healthy. It'll be impressive.
That's the specification.
FAQs
Q: How big should an arowana aquarium be?
A: Tank length should be at least 3x the adult fish length. For a 90cm silver arowana, that means at least 270cm long. Width 60cm+, height 70cm+.
Q: Do arowana tanks need structural floor support?
A: Yes. A 1,500-liter tank weighs about 1,500 kg. Most residential floors can't handle this. You need steel beams or reinforced concrete before installation.
Q: What filtration does an arowana tank need?
A: Arowanas are messy eaters. Use a sump filter with at least 15% of tank volume. For 1,500 liters, that's a 200+ liter sump with good mechanical and biological media.
Q: How do I start specifying a large fish tank project?
A: Start with the fish, not the tank. What species? How big will it grow? Then size the tank, check the room structure, spec the filtration, and add equipment.
Q: What equipment does a large arowana tank need?
A: Dual 300W heaters (redundant), 3,000-4,000 GPH return pump, 36W UV sterilizer, and 150W LED lighting with moonlight mode.
