Tilapia usually tops the list for anyone starting out in aquaponics, since it forgives a lot of beginner mistakes and gets written about constantly. But barramundi deserves a serious look too. This species actually belongs to the catadromous group of fish and goes by names like Asian sea bass or simply “barra.” Its native range covers the Indo-West Pacific, stretching across Southeast Asia and into northern Australia, which explains why it’s such a staple in Australian and Thai cooking — the Thai dish pla kapong is built around it.

Because barramundi comes from warm coastal waters, it needs consistently warm conditions to thrive. Growers in cooler regions may find tilapia a simpler option unless they’re prepared to actively heat the tank. Barra are also fearless eaters that will go after almost anything placed in front of them, and watching one hunt is genuinely entertaining — it slaps the surface aggressively when hungry, a clear sign of its predatory instincts.

Why Barramundi Aquaponics

Barramundi isn’t the easiest first fish for a new aquaponics grower. Yes, it grows quickly, but getting fingerlings safely to full size takes some know-how. The trouble starts because barramundi fry are only about an inch long when you get them, and at that size they begin nipping at one another. Mixing them with larger, older fish makes the problem worse, and it’s common to find a fingerling missing a chunk of flesh — an injury that’s often fatal, whether the fish dies from the wound or gets finished off by its tankmates.

The fix is to raise fingerlings inside small protective cages placed within the main tank. The bar spacing keeps bigger fish from reaching in while still letting water and food through. Once your barramundi hit roughly 4 to 6 inches, the aggression toward each other settles down. Many growers simply order double the fingerlings they actually want, expecting to lose close to half along the way.

Pro’s and cons of Barramundi in Aquaponics

Here’s what to weigh before committing to a barramundi system.

Fast Growing

Few fish pack on size as quickly. A single summer season is often enough to bring barramundi to plate size, and along the way they generate a heavy load of waste that can keep a sizable grow bed well fed.

Large Waste Volume

That healthy appetite means a lot of solid waste. How much grow bed you can support depends on your tank size and stocking density, but a standard guideline is 5 to 10 gallons of water for every barramundi you keep. If you plan to raise them to a larger size over a longer period, bump that up to somewhere between 10 and 20 gallons per fish.

Fun

Even if entertainment isn’t your main goal, barramundi deliver it anyway. They’re mostly calm and easy to observe, but feeding time turns them into a thrashing, splashing spectacle not unlike koi going after food.

Water Requirements

All that eating produces a correspondingly large amount of waste. Without adequate filtration, your system’s beneficial bacteria can fall behind on converting ammonia into nitrates, and solids can build up enough to clog your plumbing. A robust filtration setup isn’t optional here — it’s essential.

Temperature

Growth stalls and fish can die if the water drops below the range barramundi need. Outside of a naturally tropical climate, you’ll likely need supplemental heating, which adds to your running costs. Barramundi can technically tolerate water as cool as 60°F, but at that temperature they mostly sit still on the bottom and barely eat — which also means your plants won’t get much nutrient input from them.

Sensitivity

Temperature isn’t the only variable that matters. Barramundi also need water that’s rich in dissolved oxygen, and they’re intolerant of both elevated ammonia and swinging pH levels. Aim to hold the water between 77°F and 86°F, keep pH in the 6.5 to 7.2 range, and don’t let ammonia exceed 2ppm.

Predatory Nature

These are genuine predators — if a barramundi were your size, it wouldn’t hesitate to come after you. Practically speaking, that means you’ll want enough cages or a separate holding tank on hand, or your younger fish will end up as food for the larger ones, undermining the whole system.

Barramundi temperature

Barramundi do best when the water stays between 77°F and 86°F. Drop below that and they quickly turn sluggish and can die; push much above it and they start to struggle as well.

Barramundi growth rate

As already noted, barra pack on weight fast. Expect around 1 pound of fish at the 5-month mark, roughly 2 pounds by 7 months, and up to 4 pounds within a year — though tank space, stocking, and available food will all affect the exact numbers.

The whole life cycle moves quickly from the start. Fertilized eggs hatch in as little as 17 hours when water sits between 80°F and 85°F. For the first day or two, the newly hatched fish live off their yolk sac, and by around 50 hours old they’re ready to start eating. Microalgae serves as their food for roughly the first week, after which they can move on to brine shrimp around day 8. By 45 days, they typically measure 2 to 4 inches and can be managed like adult fish from that point forward, eventually reaching a maximum length of about 15 inches.

Barramundi for Aquaponics FAQ

What do barramundi eat?

As opportunistic predators, barramundi will eat nearly anything you offer — worms, shrimp, yabbies, feeder fish, and commercial pellets all work well. Don’t be fooled by their generally calm demeanor; feeding time brings out aggressive, splashy thrashing.

Is barramundi safe to eat?

Absolutely — it’s nutritious and delicious. Thanks to the fast growth rate, you can stock fingerlings in spring and be harvesting plate-sized fish by autumn. The catch is that your system will sit fishless through the coldest part of the year unless you switch to a cold-tolerant species like trout or arctic char for the winter months.

Beyond great flavor, barramundi also brings solid nutritional value, including omega-3 and omega-6 fatty acids.

How big do barramundi grow?

Fed well, barramundi can reach around 12 to 15 inches within a year — a substantial fish. If you’d rather harvest earlier, they’re also perfectly good to eat at 6 to 7 months old, when they’re typically around 2 pounds and 6 to 8 inches long.

Can I Keep Them With Other Fish?

Barramundi tend to attack anything smaller than themselves and may even challenge fish of similar size. It’s best to keep them in a tank on their own, unless the other fish are meant to become barramundi food.

Where can I buy barramundi fingerlings or fry?

If you’re not located in Thailand or Australia, your best option is usually an online search. Some regions do have local aquaponics suppliers stocking barramundi, but shopping online will generally give you a wider selection to choose from.