How to Set Up a Shrimp Tank

The short version

• A cherry shrimp (Neocaridina davidi) colony lives in as little as 5 gallons, with no heater in a normal room and a gentle sponge filter, or no filter at all in a heavily planted jar.
• The water decides everything: shrimp need GH 4 to 14 to molt a new shell, a pH from 6.5 to 8.0, and zero copper, which hides in some fish medicines and plant fertilizers.
• Their food is biofilm, the invisible layer that grows on moss, wood, and glass, so a mature, planted tank feeds the colony for free.
• Start with 10 or more shrimp, wait until the tank is cycled and biofilm-rich, and a healthy colony doubles in a season.

A shrimp tank is the closest thing in the hobby to a self-feeding system: a colony of cherry shrimp grazes biofilm and leftovers all day, breeds with no help, and asks for almost nothing but water that holds steady. The catch is that "holds steady" is carrying a lot of weight in that sentence. Shrimp react to a swing in hardness or a trace of copper harder than any beginner fish, and most first colonies are lost in the opening month to water that was never right, not to anything you could see coming.

Get the water and the biofilm right before a single shrimp goes in, and the rest of the build is small and cheap. Here is how to set up a tank a Neocaridina colony will actually hold and grow in.

What a shrimp tank actually needs

A shrimp tank is a small, mature, planted tank with the right mineral content and no copper. Cherry shrimp (Neocaridina davidi) run happily from 65 to 78 F, so a heater is optional in most rooms, and they top out near 1.2 inches, which is why 5 gallons holds a real colony rather than a token pair. Three things carry the build: hardness in the 4 to 14 dGH band so they can molt, a pH somewhere from 6.5 to 8.0 that does not lurch, and enough plant and wood surface to grow the biofilm they eat. Get those three right and the shrimp handle their own feeding and breeding.

The tank: small, but not too small

A rimless nano cube in the 2 to 5 gallon range is the classic shrimp home, and a 5-gallon is far more forgiving than a 2-gallon because a larger water volume swings temperature and hardness more slowly. Under about 2 gallons the parameters move fast enough that a beginner struggles to hold them, so treat 5 gallons as the practical floor for a first colony. A wide-mouth glass jar can work as a genuine no-filter home too, but only for shrimp and snails, never fish, since a jar cannot buffer a fish bioload. Whatever the vessel, plan for at least 10 shrimp so the colony has the numbers to breed.

Water: the hardness number that decides the tank

General hardness is the parameter most beginners never test and the one that kills the most shrimp. A shrimp molts as it grows, shedding its shell and building a new one from minerals in the water, and below roughly GH 4 there is not enough calcium and magnesium to finish the job. Aim for GH 6 to 8 for a first colony, keep pH between 6.5 and 8.0, and hold the temperature in the 65 to 78 F band. If your tap is very soft or you use RO water, rebuild the minerals with a GH/KH+ remineralizer made for Neocaridina, and read the result with a GH and KH test kit before the shrimp arrive.

Hardscape and plants: growing the food

The plants and wood in a shrimp tank are not decoration, they are the pantry. Java moss (Taxiphyllum barbieri) is the default shrimp cover: it holds biofilm that newborn shrimp graze, tolerates 64 to 82 F, and asks only that you tie it down so it does not drift. Cholla wood earns its place the same way, growing the biofilm baby shrimp eat and softening slowly as they work it, and it sinks after a short soak while adding gentle tannins. Add a marimo moss ball (Aegagropila linnaei), which prefers cooler water from 59 to 77 F and gets picked over all day, plus a few magnolia or oak leaves as leaf litter that releases still more biofilm as it breaks down.

Cycle first, then wait for the biofilm

A shrimp tank has to be cycled like any other: ammonia and nitrite both reading zero on a liquid test, which usually takes 4 to 6 weeks. Shrimp are so sensitive that it pays to go further and let the tank mature for 2 to 3 months, because a young tank has thin biofilm and a mature one is carpeted in the food a colony needs. A sponge filter is the right filtration here: it is air-driven and gentle, it grows a large bacteria colony on the foam, and its slots are too fine to swallow a shrimplet the way a hang-on-back intake will. In a heavily planted 5-gallon the plants and substrate can carry the load with no filter at all, but the sponge is cheap insurance.

Adding the colony and letting it grow

Start with 10 or more shrimp, because a colony needs genetic spread and safety in numbers to establish. Acclimate slowly, ideally by dripping tank water into their bag over 1 to 2 hours, since a fast change in hardness is the shock that stuns freshly shipped shrimp. Feed lightly and rarely, a piece of blanched vegetable or a pinch of prepared food once or twice a week, because the biofilm is the main course and overfeeding just fouls the water. A settled female carries 20 to 30 eggs under her tail, and a stable colony can double inside a season, at which point a Malaysian trumpet snail or two makes a useful substrate partner that aerates the sand and self-limits to the available food.

The honest failure mode: copper and a soft-water molt

Two failures account for most dead colonies, and both are about water, not luck. Copper is lethal to shrimp at levels that fish shrug off, and it rides in on some fish medicines and on certain plant fertilizers, so read every label before it touches a shrimp tank. The second is the failed molt: in water under about GH 4 a shrimp cannot build its new shell and gets stuck halfway, a preventable death that comes down to minerals you can add before there is ever a problem. Notice that both fixes are design choices made at setup, hardness in range and copper kept out, and if a shrimp ever looks genuinely sick rather than under-provisioned, that is a call for a veterinarian, not a guess from a forum.

Frequently asked questions

Do shrimp need a filter?

Not always. A heavily planted 5-gallon can run on plants and substrate alone, the same biology a no-filter planted tank relies on. Most keepers still add an air-driven sponge filter for water movement and a bigger bacteria colony, and it is the one filter that will not shred baby shrimp. If you do run a hang-on-back or canister filter, cover the intake with a sponge or mesh.

Do shrimp need a heater?

Usually no. Cherry shrimp are comfortable from 65 to 78 F, which covers most heated rooms without any equipment. They actually breed well at the cooler end and live longer there, so an unheated tank in a stable room is fine. Add a heater only if your room drops below the low 60s, and keep the temperature steady rather than chasing a number.

How many shrimp should I start with?

Ten is the sensible minimum, and more is better. A colony needs numbers for genetic diversity and for the security that brings shrimp out into the open to graze and breed. Starting with two or three is how people end up with a tank that never establishes. Buy 10 to 15 of one color strain and let them multiply.

Can shrimp live in a jar with no filter?

Yes, within limits. A wide-mouth jar of 1 to 3 gallons, packed with moss and lit by a window or a small lamp, is a genuine no-filter home for a cherry shrimp colony. The limit is stability: the smaller the water volume, the faster the parameters swing, so keep the jar out of direct sun and top off evaporation with dechlorinated water. Stock only shrimp and snails in a jar, never fish.

Once the colony is holding, the next questions are all about who else can share the water and how to keep the tank stable as it grows. Run your build through the build planner for a stocked, balanced starting point, compare parameters in the livestock database, or read the rest of the build guides. A betta tank is the natural next build, and a planted tank without CO2 or a nano tank covers the low-tech planting a shrimp colony wants.