Sulawesi Shrimp Community Tank: What Can Actually Live With Them

Your Sulawesi shrimp tank is running well, and now you’d like something else living in it. You can build a community tank around these shrimp, but anything you add has to live permanently at 79-86°F (26-30°C) and pH 7.5-8.5, leave shrimplets alone and leave the grazing film to the colony. That rules out nearly every fish sold as peaceful. What’s left is Sulawesi rabbit snails, other Sulawesi shrimp lines and a small, managed group of Neocaridina.

What a tankmate has to survive in a Sulawesi shrimp tank

A tankmate has to survive the water first, then leave the shrimplets and the grazing film alone. Most compatibility advice starts with behavior, but here it starts with chemistry. The water these shrimp need is the part almost nothing else tolerates, and you hold it there permanently. So ask three questions of any animal before you ask whether it’s peaceful.

First, can it live in these numbers for its whole life?

Second, will it eat shrimplets? Newly released Sulawesi shrimp are tiny, and they graze across the same open rock the adults do. That’s exactly where a small hunting mouth finds them. Treat every fish as a shrimplet eater until you’ve got evidence for that species. A fish sold as shrimp safe can still take babies, and sometimes adults.

Third, does it eat the same food? These shrimp live off the biofilm, diatoms and algae growing on rock and glass. An animal that grazes those surfaces isn’t a neutral addition, even if it never touches a shrimp. It’s competition for the one food you can’t simply top up.

Fail any of the three and the answer’s no. Pass all three and you’ve still got the bioload question below.

Why warm alkaline water leaves less room for extra animals

Warm, alkaline water puts more of any ammonia into its harmful form and holds less oxygen, so every extra animal costs more here than in a cooler tank. That’s the part the tankmate lists skip, and it’s the reason the honest list of the best tank mates for Sulawesi shrimp is so short. The same waste reading isn’t equally dangerous in every tank.

Total ammonia sits in two forms in water, the ammonium ion and un-ionized ammonia. It’s the un-ionized form that drives toxicity in aquatic animals, and the split moves with the water. The ratio of un-ionized ammonia to ammonium rises roughly tenfold for each whole pH unit. It rises roughly twofold for each 10 degree Celsius rise between 0 and 30 degrees Celsius.¹ A Sulawesi tank is warm and alkaline by design, so it sits at the end of that relationship where more of any ammonia present is in the harmful form.

Warm water also holds less dissolved oxygen than cool water.² So the tank that punishes waste hardest is the same tank with the smallest oxygen buffer to deal with it. Add a fish, a second shrimp colony and a few large snails, and you’ve raised both the waste load and the oxygen demand. You’ve done it in a system that had less headroom for either one to start with.

The three tankmates worth considering, and what each one costs

Rabbit snails, other Sulawesi shrimp lines and a few Neocaridina pass the three tests, and each one still carries a cost. Here’s where the five candidates people usually ask about land. The cost is the part worth deciding on before you order.

Sulawesi rabbit snails, the only genuinely native option

Rabbit snails are the one animal here that actually lives alongside these shrimp in the wild. The genus Tylomelania is restricted to the same two ancient lake systems the shrimp come from, Lake Poso and the Malili lakes of Matano, Mahalona and Towuti.³ So the water suits them, and nothing about them hunts a shrimp.

The cost is size and reproduction. These snails brood their young inside the body and release them already shelled, in some species close to 2 cm long.⁴ That’s a large animal turning up in your tank at intervals you don’t control, and each one eats and produces waste from day one. Rabbit snails are usually kept a touch cooler at the top end than Sulawesi shrimp, too. If you run the tank at the warm end of the band, that’s the setting to watch. Before you put Sulawesi shrimp and rabbit snails together, work out how many your tank can actually carry.

Other Sulawesi shrimp lines in the same tank

Mixing two or three Sulawesi lines is the easiest addition chemically. They want the same water, and none of them will hunt the others. The whole cost sits in the offspring. If you ever plan to sell or trade a line, or just keep it recognizable, a shared tank puts that at risk. Do Sulawesi shrimp lines really crossbreed? The evidence is thinner than the confident charts online suggest. Our advice is simple. If the line matters to you, give it its own tank. If you just want a colorful tank for yourself, mix freely and enjoy whatever turns up.

There’s a second cost that’s easy to miss. Two colonies graze the same rock, so a mixed tank needs more grazing surface than a single species tank of the same volume, not the same amount split two ways.

A small group of Neocaridina, kept small on purpose

Neocaridina are the one addition with a real behavioral argument behind them, and the one most likely to go wrong. A Neocaridina colony is usually kept up to 78°F (26°C), a little below where a Sulawesi tank starts. Putting cherry shrimp in here means running them warm for life. They can cope: in a 90-day study they grew and bred at 82°F (28°C), though breeding failed at 90°F (32°C).⁵ In some of our own Sulawesi tanks a small group lives and breeds at up to 86°F (30°C). Hardy doesn’t mean any heat, though, and any that hide all day or keep dying belong in cooler water.

Note the number. About five, not a colony. A group that establishes itself will graze the same film your Sulawesi shrimplets depend on, so the number is the whole point. Go this route and you’re signing up to pull cherry shrimp out regularly for the life of the tank, so decide now where they’ll go. If you’d like the full temperature and competition picture first, read up on keeping Sulawesi shrimp with Neocaridina before you order either one.

Why fish stay out, including the Sulawesi ricefish

Fish stay out because nearly every candidate fails the water test or the shrimplet test, and the one fish from the region fails on diet. Boraras, chili rasboras, celestial pearl danios and the small tetras turn up on every list. Put each one through the first test yourself before you believe the list. A mixed tank only works when every species overlaps on temperature, water chemistry, behavior, space and feeding.

Then run the second test, which is where most of them stop anyway. Plenty of peaceful nano fish eat shrimplets, which puts them among the fish to avoid with Sulawesi shrimp. Otocinclus are a different case. They rarely bother adult shrimp, but they’re sensitive animals that do best in a mature tank with plenty of grazing, and grazing surface is exactly what you’re trying to keep for the shrimp.

What about the Sulawesi ricefish? It’s the one fish that genuinely shares the region and broadly suits the water, and it still fails on diet. Gut contents of an endemic Sulawesi ricefish show a fish whose main food is small crustacean plankton.⁶ A fish built to hunt small crustaceans, in a tank whose floor is covered in small crustaceans, isn’t a compatibility question you want to test.

Predation is decisive here, not merely annoying, because the colony replaces what it loses so slowly. Published counts of wild Sulawesi Caridina put the broods at the small end for dwarf shrimp. Cardinal shrimp females carried 8-14 eggs each in the material examined.⁷ The young aren’t quick either. In the one controlled rearing trial published for the species, shrimp started at an average total length of 1.445 cm. In the best of four feed and shelter treatments, they gained only about 0.119 cm over 30 days.⁸ A cherry shrimp tank absorbs a fish eating babies. A Sulawesi tank doesn’t.

Weighing up one particular species instead of the whole category? The case by case assessment of fish tankmates for Sulawesi shrimp works through water, adult size and feeding position one fish at a time.

How to stock a Sulawesi community tank without losing the colony

Stock the shrimp first, always, and by a wide margin. If you’ve got a candidate that passes all three tests, the order you do things in matters more than the stocking list itself.

1. Get the shrimp colony established and breeding on its own before you add anything. A tank that’s still finding its feet has no spare capacity to absorb a new animal.
2. Grow more grazing surface than you think you need. More rock, more established film, and do it before the extra mouths arrive.
3. Add one kind of animal at a time, in small numbers, and leave weeks between additions. If something goes wrong, you’ll want to know what caused it.
4. Take a nitrate reading before the addition and again a week or two later. That comparison is the only honest measure of what you’ve just put into the system.
5. Keep a headcount you can actually complete. If you can’t find every snail, you can’t tell when one has died.

Stocking is also the moment to be honest about what you’re buying into. A tank built around tank-bred Sulawesi shrimp asks for steady conditions long before it asks for variety. Get the colony right first. Then decide whether variety is worth the margin it costs you.

When a single species tank is the better call

Go single species if the tank is new or small, or if you’ve lost shrimp before and haven’t yet found out why. We know a tank with one kind of animal in it sounds like a compromise. In this group it usually isn’t. A Sulawesi tank that holds steady numbers, keeps waste low and grows a thick grazing film is already doing something difficult, and every animal you add makes each of those three jobs harder.

Small here means a tank where a single dead animal shifts the readings. Single species is also the better call if you want the colony to grow. Add a tankmate once the colony has been stable and breeding for months, you’ve got surface to spare, and you’ve got a specific reason for that specific animal. A general wish for company isn’t a reason. And if the reason is that the tank looks empty, the answer is more rock, not more animals.

What the research says about Sulawesi shrimp tankmates

The studies on the tankmates themselves weren’t done in Sulawesi shrimp tanks, so read them as background on each animal and not as a measurement of yours.

Rabbit snails have a reproductive strategy unusual enough to get its own anatomical study. Tylomelania broods its young inside the body and produces embryos continuously, not in seasonal batches. The juveniles arrive already shelled, and in some species they’re close to 2 cm long at release.⁴

The cherry shrimp figures come from a 90-day study of how temperature affects the biochemical composition, growth and reproduction of the red cherry shrimp. The shrimp grew and bred at 82°F (28°C), and breeding failed at 90°F (32°C).⁵ That’s a measurement on cherry shrimp kept on their own, which is why we’d still watch any group you run in Sulawesi water.

The ricefish diet comes from the gut contents of Oryzias eversi, an endemic fish from Tana Toraja in South Sulawesi. It turned out to be an omnivore carnivore whose main food was small crustacean plankton, with Cyclops larvae the dominant item.⁶ That’s one ricefish species from one area, and it’s the evidence behind keeping ricefish out of a shrimp tank.

References

8 Sources

1. Aquatic Life Ambient Water Quality Criteria for Ammonia, Freshwater, U.S. Environmental Protection Agency, Office of Water, April 2013.
2. Dissolved Oxygen and Water, U.S. Geological Survey, Water Science School.
3. The species flocks of lacustrine gastropods: Tylomelania on Sulawesi as models in speciation and adaptive radiation, Hydrobiologia 615, Springer, 2008, abstract.
4. Anatomy of an adaptive radiation: a unique reproductive strategy in the endemic freshwater gastropod Tylomelania (Cerithioidea: Pachychilidae) on Sulawesi, Indonesia, and its biogeographical implications, Biological Journal of the Linnean Society 85(4), 2005, abstract.
5. Tropea, Stumpf and Lopez Greco, Effect of Temperature on Biochemical Composition, Growth and Reproduction of the Ornamental Red Cherry Shrimp Neocaridina heteropoda heteropoda (Decapoda, Caridea), PLOS ONE 10(3): e0119468, 2015.
6. Habitat and food habits of the endemic fish Oryzias eversi in Tana Toraja, South Sulawesi, Indonesia, Biodiversitas 24(9): 5137-5145, 2023.
7. Radiation of endemic species flocks in ancient lakes: systematic revision of the freshwater shrimp Caridina from the ancient lakes of Sulawesi, Indonesia, with the description of eight new species, Raffles Bulletin of Zoology 57(2): 343-452, 2009.
8. Effect of Using Different Shelter and Feed Types on Growth and Survival Rate of Sulawesi Endemic Ornamental Shrimps (Caridina dennerli), Jurnal Ilmiah PLATAX 13(1): 191-204, 2025, journal PDF.