Do Sulawesi Shrimp Need an Air Stone or Is a Filter Enough?

A filter is enough for Sulawesi shrimp when it keeps the water surface moving. Filters driven by an air pump, airlift undergravel plates and trickle systems already do that, so a separate air stone is optional. A sealed canister filter with a submerged return usually leaves the surface flat, and that setup does need an air stone or a spray bar at the waterline. This guide covers the lake-system Caridina group sold as Sulawesi shrimp, including Cardinal, Oiran, White Sock and Blue Leg lines.

Surface agitation

Movement of the top film of water, where oxygen actually enters and carbon dioxide leaves. This is what you’re buying when you aerate.

Flow

How fast water moves through the tank. Strong flow at shrimp level doesn’t prove good gas exchange, and a fast pump with a submerged outlet can leave the surface completely still.

Why Warm, Alkaline Sulawesi Tanks Run Closer to the Oxygen Limit

Most shrimp keepers can be relaxed about aeration because their tanks sit cool and near neutral. A Sulawesi tank gives up that margin twice over. The typical reference range for this group is 79-86°F (26-30°C) at pH 7.5-8.5, which is warmer and more alkaline than almost anything else in the freshwater shrimp hobby. Both of those numbers work against you at the same time, and that’s the real reason aeration gets discussed so much for these animals.

Warm Water Holds Less Oxygen at Every Point in the Sulawesi Range

The ceiling on dissolved oxygen falls as water warms. At sea level, fresh water saturates at roughly 8.1 mg/L at 79°F (26°C) and only about 7.6 mg/L at 86°F (30°C).¹ Those are ceilings, not readings. They’re the most your tank could hold if gas exchange were perfect and nothing in the tank were consuming oxygen, which is never the case.

Running at the warm end of the range therefore costs you oxygen headroom before a single shrimp has taken a breath. It doesn’t mean you should keep the tank cool. It means the same interruption in gas exchange has less slack to absorb at 86°F (30°C) than it would in a cooler tank.

Alkaline Sulawesi Water Turns Ordinary Ammonia Into a Faster Problem

Ammonia in water sits in two forms: ionized ammonium, which is comparatively mild, and un-ionized ammonia, which is roughly a hundred times more toxic. The split between them is set mostly by pH and temperature, and the toxic share climbs as both rise.² Read against the published fraction table, water at pH 7.5 and 79°F (26°C) holds close to 2 percent of its total ammonia in the toxic form. The same total ammonia at pH 8.5 and 86°F (30°C) holds close to 20 percent.²

That’s the same tank, the same test kit reading, and roughly ten times the toxic exposure depending on where in the accepted range you sit. It’s why a small feeding mistake behaves differently here than in a Neocaridina tank, and why the biofilter has to keep working without pause.

A Sulawesi Biofilter Competes With the Shrimp for the Same Oxygen

Nitrification is an aerobic process. The bacteria that convert ammonia to nitrite and nitrite to nitrate need oxygen and alkalinity to function, and if oxygen isn’t sufficient they slow down or die off, which lets ammonia and nitrite climb.² Published aquaculture guidance treats a drop below 5 mg/L as the point where low oxygen begins limiting that conversion.²

The warm alkaline water itself is set by the Sulawesi shrimp care parameters; this page is about what that water does to oxygen.

So aeration in a Sulawesi tank isn’t only about the shrimp breathing. It protects the process that keeps the water non-toxic in exactly the conditions where ammonia is most dangerous. A tank that loses gas exchange loses both at once, which is why the failure tends to look sudden.

Does Your Sponge, HOB or Canister Filter Aerate a Sulawesi Tank Enough?

Air stones and filters aren’t really competing products. A rising bubble stream transfers some oxygen directly and, just as importantly, carries water up so it turns over at the surface, which is how diffused aeration systems are designed to work.³ Any filter that produces the same effect is doing the air stone’s job. What follows is a reading of each common design against that single test, so match your equipment to the row rather than to the general reputation of the category.

There’s an honest limit to that table. It reflects how each design moves water and where it puts the return, and no published study compares these filter types specifically in Sulawesi shrimp systems. Treat it as a starting verdict that the next section asks you to confirm in your own tank.

At Shrimp Aquatics, our Sulawesi systems use biological filtration together with a Kaldnes moving-bed filter. The combination gives us strong aeration and active biological media, but we tune the outlet so the shrimp aren’t pushed around while grazing. The goal is high oxygen with gentle movement at shrimp level. Tank size, bioload, media volume and pump output still change what works for you.

Which filter for Sulawesi shrimp suits your colony is a separate question from whether it aerates enough, and the two answers don’t always agree.

Test Your Own Sulawesi Tank Instead of Trusting the Filter Label

Filter categories are a shortcut. Two keepers running the same model can get opposite results depending on water level, outlet angle and how much surface film has built up. Check the tank in front of you, and check it after any change to the hardscape, water level or filter media.

• Look along the surface at eye level. You want continuous visible ripple, not a mirror.
• Measure dissolved oxygen with a test kit or meter rather than inferring it from flow.
• Test ammonia and nitrite at the same time. A stalling biofilter and low oxygen usually appear together.
• Check the surface for an oily protein film, which blocks gas exchange even when a pump is running.
• Repeat the check on the warmest afternoon of the week, when the ceiling is at its lowest.
• Don’t judge oxygen by how fast the shrimp are moving. Reduced grazing and lethargy are late signals, and low oxygen changes respiratory metabolism in freshwater decapods well before behavior makes it obvious.⁴

If the surface is flat and the reading is low, change one thing at a time. Raise the outlet, fit a spray bar above the waterline, or add an air stone, then measure again after the tank has settled. Sulawesi shrimp respond poorly to abrupt change, so avoid rebuilding the whole filtration system in a single afternoon.

Add a Backup Air Stone Even When Your Sulawesi Filter Is Enough

Adequate under normal running conditions isn’t the same as safe when something stops. Because the oxygen ceiling is already low at these temperatures and the biofilter’s ammonia conversion depends on oxygen, a Sulawesi tank has less time in hand after a failure than a cooler tank does. Many experienced keepers run a second, independent source of aeration for that reason alone.

A surface film deserves its own mention. Mature Sulawesi tanks are meant to grow biofilm and algae, and that same productivity can leave a protein layer sitting across the top of the water. A bubble stream breaking through that layer keeps the exchange open in a way that a smooth horizontal current won’t.

Aeration is one part of building a stable tank, and the beginner guide to keeping Sulawesi shrimp puts it beside heating, hardscape and filtration where it belongs.

The decision at the end of all this is narrow and practical. Look at your surface, measure your oxygen, and match the result to your filter type. If the filter is already moving water across the air boundary, you don’t need an air stone to keep Sulawesi shrimp. If it isn’t, no amount of flow rate or media volume will make up for it, and adding aeration is the correction to make before you add livestock.

Settle the aeration question before you order tank-bred Sulawesi shrimp, because a tank that runs close to its oxygen limit shows it first in the newest arrivals.

References

4 Sources

1. DOTABLES: Dissolved oxygen solubility tables, U.S. Geological Survey, accessed July 20, 2026.
2. Ammonia in Aquatic Systems (FA16/FA031), University of Florida IFAS Extension, revised May 13, 2024, accessed July 20, 2026.
3. The Role of Aeration in Pond Management (FA6/FA021), University of Florida IFAS Extension, revised September 16, 2024, accessed July 20, 2026.
4. Respiratory Metabolism Responses of Chinese Mitten Crab, Eriocheir sinensis and Chinese Grass Shrimp, Palaemonetes sinensis, Subjected to Environmental Hypoxia Stress, Frontiers in Physiology, 2018, accessed July 20, 2026.