How Much Should You Feed Sulawesi Shrimp?

You’ve got a tin of shrimp food, a tank of Sulawesi shrimp and a label telling you to feed every day. Feed far less than that: a portion small enough that nothing is left for you to take back out. In an established tank the biofilm and algae on the hardscape are what these shrimp mainly graze, and prepared food only tops that up. No feeding ration has been measured and published for Sulawesi shrimp (Caridina spp. from the Sulawesi lake systems), so there’s no gram figure to copy. Your rock and your leftovers have to tell you instead.

Why the biofilm in a Sulawesi tank sets the portion, not a chart

The grazing surface sets the portion because mature biofilm, aufwuchs and algae are important grazing resources for this group. On well colonized rock they’re available all day, not just at feeding time. That’s why a per shrimp weight is the wrong unit for the question. Picture a three month old tank with a thin film on smooth stones next to a two year old tank with textured rock under a soft green layer. Both can hold the same twenty shrimp and need very different amounts of prepared food. In one, the shrimp are already eating between your feedings. In the other, they aren’t.

So where do you start? Look at the rock, not the headcount. If the hardscape carries a visible film and the shrimp are working over it steadily, prepared food is a supplement and the portion can be tiny. If the surfaces look scrubbed and pale, the tank is producing less than the colony is taking. The fix is more grazing surface and a longer light period, not a bigger pinch of powder.

Acceptance varies too. Some Sulawesi species and lines take prepared food readily, and others show very little interest in it, so a portion that vanishes in one tank can sit untouched in another. Watch what your own animals do with it before you settle on an amount.

How long a Sulawesi portion should stay in the tank

A portion should stay in only as long as the shrimp are actually eating it, and never overnight. How often a portion goes in is a separate decision, and how often to feed Sulawesi shrimp depends on how fast your grazing surfaces recover. For the portion itself, the risk isn’t the food. It’s the fraction that stays in the tank and breaks down.

Lift whatever is left before the lights go out, so nothing sits in warm water until morning. Powder is harder to take back out once it has spread, which is one more reason to start a powder dose small. Offer a little, watch what happens to it, and let the result decide the next portion. You’ll know you’ve got it about right when these hold:

• Nothing is left to siphon out after the shrimp have finished with it.
• The film on the hardscape is still there the next day, so the colony isn’t stripping its grazing base between feedings.
• The shrimp go back to grazing the rock and leave the spot where the food went in.
• If you’re regularly removing uneaten food, the portion was too big, and the next one should be smaller, not the same size offered less often.

What a shrimp powder’s label dose assumes about your tank

A label dose assumes a stated water volume and stocking level, and it knows nothing about what your rock already produces. Of everything Sulawesi shrimp eat, powdered biofilm foods are the format that suits a grazing colony, and they come with real dosing instructions, which is more than any Sulawesi care sheet offers. GlasGarten’s instructions for Bacter AE, for roughly 120 liters of aquarium water, are half a measuring spoon once daily at low stocking, one spoon once daily at normal stocking and one spoon twice daily at high stocking.¹ One spoon holds approximately 0.5 g, and the manufacturer suggests you start at half the dosage for about a week.¹ Spirulina powders and wafers raise the same portion question. Sulawesi shrimp eat spirulina readily enough, so what matters is the share they leave behind.

Read that for what it is: the manufacturer’s instruction for its own product, written for shrimp keeping in general. In a mature Sulawesi tank that’s lightly stocked and well grazed, a daily dose at that scale is far more organic input than the colony is taking out of the water. Treat the label figure as the ceiling, and work up from a much smaller amount instead of down from the tin.

That measuring spoon is also the easiest way to measure a portion. Level it once so you can see what the label’s daily amount for a normally stocked 120-liter tank looks like. Then offer a small fraction of it, scaled down again if your tank holds less water. A pinch from the tip of the spoon is a sensible first portion for a small colony. A full spoon isn’t. Pellets and wafers are easier still, because you can count them: start with one small piece and change by one at a time. Read their labels the same way as the powder’s. A label that doesn’t know your volume, stocking and grazing can’t know what your rock already provides.

Why an overfeed costs more in warm alkaline Sulawesi water

An overfeed costs more here because warm, alkaline water turns a bigger share of the ammonia from rotting food into its toxic form. Total ammonia in water sits in two forms, the ammonium ion and un-ionized ammonia, and it’s the un-ionized form that drives toxicity. High external concentrations reduce or reverse diffusive gradients and cause ammonia to build up in internal tissues and blood. The share present as un-ionized ammonia isn’t fixed. The ratio of un-ionized ammonia to ammonium ion in fresh water increases by tenfold for each rise of a single pH unit, and by approximately twofold for each 10 degree Celsius rise in temperature from 0-30 degrees Celsius.²

A Sulawesi tank runs at pH 7.5-8.5 and 79-86°F (26-30°C), the top end of both of those relationships. So the same reading on the same test kit means a larger share of the toxic form than it would in a cooler, more acidic Caridina tank. Decomposing food is exactly where that ammonia comes from. Warm water also holds less dissolved oxygen than cold water³, so the tank has less room to spare while it processes whatever you added. Neither relationship gives you a safe ammonia level or a minimum oxygen level for shrimp. What they give you is direction.

None of that makes these shrimp fragile. It makes the same mistake more expensive. That’s why the safe direction of error in this group is feeding too little, and why leftovers come out instead of being left to break down.

Feeding a Sulawesi tank that’s still building its grazing surfaces

Feed a tank that’s still building its grazing surfaces less, not more, because supplemental feeding can’t make up for an immature system. We know a new tank is where the urge to pour food in is strongest. It’s also where food does the most damage. The biological filter and the grazing surfaces both take time. Add prepared food to a tank that has neither, and the organic load lands in the system least able to process it.

While a tank is maturing, the levers that matter are light on the hardscape, patience, and confirmed zero ammonia and nitrite before shrimp arrive. Prepared food during that period is there to seed microbial growth, not to feed animals, and it comes back out. Once shrimp are in, keep the portion smaller than you would in a settled tank for the first weeks, and let the film build up ahead of the colony.

Will feeding more give you bigger Sulawesi shrimp?

No. Like other crustaceans, shrimp only grow when they cast the exoskeleton at a molt,⁴ so a bigger portion adds waste without adding size, for the same reasons that rule out feeding Sulawesi shrimp more often.

Adjusting the portion as your Sulawesi colony grows

Raise the portion in small steps as the colony grows, and add grazing surface when the film stops keeping up. A growing colony changes both sides of the equation at once. There are more mouths, and there’s more grazing pressure on the same rock, so the surfaces get cleaned faster and the tank produces less between feedings than it used to. Keep applying the leftovers test after each step. More textured rock feeds the colony without adding anything to the water. It works in reverse too: after losses, or once you’ve moved shrimp out, cut the portion first and let the leftovers test bring it back up.

Stocking lightly at the start keeps the whole question simple, because a small group in a well grazed tank barely needs you. The tank-bred Sulawesi shrimp we breed are listed line by line, so you can begin with one group and let it build. Feed the tank you have this week, not the colony you’re hoping for next year.

References

4 Sources

1. Bacter AE, for bio film and shrimp rearing feed, GlasGarten, updated December 25, 2024.
2. Aquatic Life Ambient Water Quality Criteria for Ammonia, Freshwater (2013), U.S. Environmental Protection Agency, Office of Water, April 2013.
3. Dissolved Oxygen and Water, U.S. Geological Survey, Water Science School, updated August 24, 2026.
4. Farming freshwater prawns, biology chapter, Food and Agriculture Organization of the United Nations, FAO Fisheries Technical Paper T428.