Your Sulawesi tank is cycled, and the stocking list in your head has more than shrimp on it. Keep Sulawesi shrimp in a tank of their own: the only tankmate we’d add on purpose is a Sulawesi rabbit snail, and even that’s a waste decision more than a chemistry one. Just don’t read “alone” as one shrimp, because a single shrimp in a big rock pile is a mistake of its own.

A species-only tank still needs a group of Sulawesi shrimp

Keep one species, but keep it as a group. When people ask whether these shrimp should be kept alone, they usually mean two things at once. One is whether the tank should hold anything else. The other is whether a shrimp is fine by itself. The answers point in opposite directions, so it’s worth splitting them up.

Buy a group, not a pair, and not one. These shrimp are shy by nature, and a handful of them spread through a rock pile will give you a tank that looks empty most of the day. A group also gives you both sexes without having to sex anything, which matters because the numbers coming out the other end are small. Published counts from wild-caught females put Caridina dennerli at 8 to 14 eggs on the pleopods at the time of collection, and across the Sulawesi lake species in that revision the per-brood counts ran from 8 to 80 depending on the species.¹ Those are wild measurements from small samples, not what your tank will do, but they set the scale: a Sulawesi colony rebuilds itself slowly, a dozen or so eggs at a time.

That slow rebuild runs through the rest of this page. Almost every question below about the best tankmates for Sulawesi shrimp comes down to the same arithmetic. Whatever you add either takes from that small cohort, or takes from the water quality the cohort depends on.

Why one extra animal costs more in a Sulawesi tank

Every extra animal adds waste to water that’s less forgiving of waste than any other shrimp setup. That’s the part that surprises people coming from a cherry shrimp tank. The shrimp aren’t fragile in some mysterious way. It’s a chemistry problem, not a husbandry opinion.

The water we keep Sulawesi lake shrimp in
Temperature	79-86°F (26-30°C)
pH	7.5-8.5
GH	4-8 dGH
KH	3-6 dKH
TDS	150-250 ppm
Nitrate	Under 10 ppm as a cautious target

Look at the top two rows together. Total ammonia in water splits between the ammonium ion and un-ionized ammonia, and the un-ionized form is the one that drives ammonia toxicity in aquatic animals. That split moves with the water: the ratio of un-ionized ammonia to ammonium ion in fresh water rises about tenfold for each single pH unit, and about twofold for each 10 degree Celsius rise in temperature between 0 and 30 degrees Celsius.² Warm and alkaline is exactly the corner a Sulawesi tank sits in. The same ammonia reading a cherry tank shrugs off at 72°F and pH 7.0 is a different event here.

Warmth costs you on the other side too. Cold water holds more dissolved oxygen than warm water, so oxygen concentration falls as temperature rises.³ Your tank is already running at the warm end before a single extra animal starts breathing in it.

So a fish in this tank is more than a mouth near the shrimplets. It’s daily feeding, and daily waste, in water that punishes waste harder than any other shrimp setup in the hobby, while the colony replaces itself a dozen eggs at a time. That’s the trade every tankmate has to be worth.

Rabbit snails are the one tankmate we would add

A Sulawesi rabbit snail is the exception because it comes from the same water. Sulawesi rabbit snails, Tylomelania spp., live in the same two ancient lake systems as the shrimp: Lake Poso and the Malili lakes, which include Danau Matano, Mahalona and Towuti.⁴ You don’t have to bend the temperature or pH to keep them, because they evolved in it.

They also won’t take over a tank the way a pond snail does. A rabbit snail releases one large, already shelled young at a time.⁵ That’s a very different stocking problem from a clutch of pond snail eggs on the glass.

The catch is what that size means for your filter. A rabbit snail is a large animal that eats a lot and passes a lot, and its waste lands in the water we just described. So treat a snail as a bioload decision: add one, leave it a few weeks, and watch your nitrate and TDS before you think about a second.

Check the readings, not the tank size

A snail per so many liters is a rule of thumb, and it’s a poor one in a tank this sensitive. Let your own nitrate and TDS readings decide whether the tank has room for another one, and go back to your test kit before you add anything at all. The practical limits, and what to watch after a snail goes in, are in our guide to rabbit snails in a Sulawesi tank.

One more thing before you order. Tylomelania gemmifera, one of the rabbit snails sold internationally in the pet trade, was assessed as Endangered on the IUCN Red List in 2018, with a decreasing population trend.⁶ It’s a good reason to ask a seller whether the snails are tank-bred or pulled from the lakes.

You lose track of which line bred with which, because breeding happens deep in the rock where you can’t see it. This is the mix people most want to build, and we get why. A rock pile carrying White Sock, Blue Leg and an orchid line looks like the display tank in your head. The trouble is you can’t supervise it. You find out which line met which only when the shrimplets are big enough to look at.

If your tank already holds two species and you want to know how seriously to take the risk before you separate them, how far the evidence goes is worked through for Sulawesi shrimp crossbreeding.

Why does it matter more here than in a cherry tank? Because of what these lines are. Caridina dennerli was assessed by the IUCN in 2018 as Critically Endangered, tagged Possibly Extinct in the Wild, under criterion A2e, with international trade recorded as a use of the species.⁷ The tank-bred lines in the hobby are, in a real sense, most of what’s left of it. Our advice is one species per tank, and if you want three lines, run three tanks.

Neocaridina can, and they’ll breed in it. They’re usually kept at 65-78°F (18-26°C), yet in a published study Neocaridina bred at 82°F (28°C) and failed to breed at 90°F (32°C).⁸ In our own Sulawesi tanks a small group of Neocaridina lives and breeds at up to 86°F (30°C). Don’t read hardy as any heat, though: any that hide all day or keep dying belong in cooler water. They also graze the same surfaces your Sulawesi shrimp graze, and a colony left to breed means steadily more mouths on those surfaces. That’s why we’d keep a small managed group at most, and never a breeding colony, in a tank built for Sulawesi shrimp.

In some of our Sulawesi systems at Shrimp Aquatics, we keep about five Neocaridina and have observed the Sulawesi shrimp remain more visible, or retreat less, when people approach the tank. That’s the one reason we’d consider it at all, and it still needs suitable temperature overlap, enough grazing surface and stocking capacity for both groups.

If you’re weighing it up seriously, the numbers on both sides, and what warm water asks of a cherry colony, are set out for Sulawesi shrimp with Neocaridina.

Bee and Crystal Caridina are a flat no, and it isn’t close. Bee shrimp are kept at 60-72°F (15.5-22°C) in soft acidic water, which shares nothing with the table above except a sliver of GH. A setting halfway between the two belongs to neither animal, and we think you’d be failing both. Splitting an existing mixed tank, and matching each half to your room, is worked through for Sulawesi shrimp and bee shrimp.

What a fish costs a Sulawesi colony

A fish costs you daily waste and a risk to every shrimplet, so it has to pass two tests. Does its documented water fall inside the band in the table above, and will it leave shrimplets alone? Most nano fish get recommended for shrimp tanks in general, not for warm alkaline ones, so look up the documented range for that exact species before you trust a shrimp-safe label. And treat shrimp-safe as meaning lower risk to adults, never safe for shrimplets.

Then there’s the quiet cost. Feeding a fish means feeding the tank daily, and you’ve already seen what daily waste does in warm alkaline water. If you have a species in mind, we’ve run the usual candidates through both tests for fish tankmates for Sulawesi shrimp. Our own answer is that the shrimp are better off without one.

Stop hitchhikers before they reach your Sulawesi tank

Treat anything wet going into the tank as a tankmate you didn’t choose. You can decide on a species-only tank and still end up with company. Plants from an unknown system can carry pests, pesticide residue or treatments that are risky to shrimp, and bags of livestock arrive with their own water and whatever is in it.

So rinse and quarantine new plants somewhere else first, keep new hardscape out until it’s been cleaned, and never pour shipping water into the aquarium. None of that is exciting. It’s still a lot easier than deciding later whether a tank you spent months maturing has to come apart.

What the research says about Sulawesi shrimp tankmates

Two pieces of research on other animals sit behind the advice above. The first is on the rabbit snail. Tylomelania brood their embryos inside the pallial oviduct, which is modified into a uterine brood pouch, and release juveniles that are already shelled. In some species those juveniles are almost 2 cm long at hatching, the largest known of any viviparous gastropod.⁵

The second is on Neocaridina in warm water. In a 90-day study, red cherry shrimp (Neocaridina) grew, matured and bred at 82°F (28°C), while breeding failed at 90°F (32°C).⁸ It’s one study on cherry shrimp. The small group of Neocaridina in our Sulawesi tanks at up to 86°F (30°C) is an observation, not a promise for every Neocaridina line.

What we would put in a Sulawesi tank, and in what order

Shrimp first, a single rabbit snail much later if the readings allow it, and nothing else. If you’re setting one up now, here’s the order we’d work in. It’s slow on purpose: every step below buys stability before the next one adds a load to it.

Mature the tank properly first, with grazing surfaces visible on the rock, not just a cycled filter.
Add one species of tank-bred Sulawesi shrimp as a group, and leave them alone apart from gentle water changes.
Give the colony months, not weeks, and watch whether your nitrate and TDS hold steady between changes.
Only then consider a single rabbit snail, and only if those readings never moved.
Leave fish, Neocaridina and bee shrimp out of it, and run a second tank if you want them.

It’s a duller answer than a stocking list, and it’s the one that keeps a colony alive. What a species-only tank gives you back is a rock pile with shrimp visibly grazing on it, which is the thing you wanted when you started reading.