TDS in Shrimp Tanks: Ranges for Neocaridina and Caridina

How do you read the shrimp TDS table?

Read each column as one shrimp’s comfort zone, and treat TDS as the summary line under the hardness rows. Crystal reds combine the lowest TDS with a KH of 0–2 dKH, almost no carbonate buffer. Cherry shrimp take more of both: 6–10 dGH and 2–8 dKH. Shrimp Science sets out the same split for the two genera in general, which is why Neocaridina are described as the harder-water shrimp.

Amano shrimp overlap both groups on TDS, but their hardness range starts at 6–15 dGH, and Practical Fishkeeping says GH should not fall below its lower end for good moulting. The Amano KH and TDS figures come from Shrimp Science alone, so treat them as less settled than the cherry and crystal red ranges. Tank-mate choices for the hardier of the three are covered in the guide to cherry shrimp tank mates.

What is TDS and how is it measured?

TDS is the total amount of dissolved material in water, and it is usually estimated from electrical conductivity rather than measured directly. SRAC Publication 4606 (Stone, Shelton, Haggard and Thomforde) explains that TDS in mg/L is typically about half the conductivity in µS/cm, a conversion factor of 0.5 mg/L TDS per µS/cm.

Because a meter reads conductivity, it counts every dissolved ion without saying which ones. Calcium and magnesium from a remineraliser, carbonate buffer and nitrate can all add to the same number. For fish culture, SRAC 4606 gives a desirable conductivity of 60–2000 µS/cm, a very wide band; shrimp keepers work to much tighter targets set by their remineraliser and their species.

Why do sources give different TDS targets for the same shrimp?

Sources differ because some describe a remineraliser’s target, some an optimum and some the full tolerance. SaltyShrimp’s product information gives targets its mineral salts are designed to hit, Green Aqua gives broader tolerance ranges, and the species care sources give their own bands. None of these is a peer-reviewed range; our fact base found no peer-reviewed TDS figure for aquarium shrimp. The table lists each figure so the spread is visible.

Which shrimp TDS figure should you follow?

Follow the range for your species from the care data, and use the remineraliser’s target only as a mixing aim inside it. For crystal reds the sources cluster closely: SaltyShrimp’s 100–150 ppm sits inside Green Aqua’s 100–200 ppm and the species range on this site. Shrimp and Snail Breeder narrows the optimum further, to 140–160 ppm within an acceptable 100–250 ppm.

For cherry shrimp the spread is wider. SaltyShrimp targets 200–250 ppm, Green Aqua allows 100–400 ppm, and Shrimp and Snail Breeder gives an optimum of 150–200 ppm within an acceptable 80–400 ppm. That breadth is the practical difference between the two genera: a cherry shrimp tank tolerates a range of tap waters, while a crystal red tank usually starts from RO water and is built up to a narrow target. The care differences between the genera are compared in the Neocaridina vs Caridina shrimp guide.

How do you raise or lower TDS in a shrimp tank?

You lower TDS by replacing some tank water with purer water, and raise it by adding a measured remineraliser. Both should happen through water changes, not by dosing the tank directly, because Green Aqua stresses that shrimp tolerate changes in temperature, pH or softness poorly and that stability matters most.

Lowering TDS

Reverse osmosis water starts near 5–10 ppm, according to Green Aqua, so mixing it into change water pulls TDS down in proportion. How much RO you need depends on your source: in USGS sampling of about 2,100 private domestic wells between 1991 and 2004, 15 percent held more than 500 mg/L of dissolved solids, the EPA’s secondary drinking-water level, mostly in the West, Southwest and south-central states. The RO/DI water for aquariums guide explains what the membrane removes and why the water must be remineralised before use.

Raising TDS

Shrimp remineralisers restore general hardness and, for Neocaridina, some carbonate hardness. SaltyShrimp’s Bee Shrimp Mineral GH+ adds GH without KH for Caridina; its GH/KH+ product for Neocaridina adds both. Mix the change water, measure TDS, GH and KH, and only then add it to the tank. GH and KH are the readings that tell you which minerals are behind the TDS number, as set out in the GH and KH explained guide, and kits for them are compared among the aquarium test kits we recommend.

Is TDS the most important number in a shrimp tank?

No. Shrimp Science states plainly that TDS is not a useful measurement on its own, and that GH, KH and nitrogen readings matter more. A TDS reading of 200 ppm could come from the right balance of calcium and magnesium, or from carbonate buffer a crystal red does not want, or from accumulated nitrate. The number is the same; the water is not.

TDS earns its place as a quick consistency check. Once you have mixed water that tests correctly for GH and KH, its TDS becomes a fingerprint: if the next batch reads the same, it was probably mixed the same way. Used that way, a TDS pen helps keep the stability that Green Aqua stresses.

Can cherry shrimp and crystal red shrimp share the same water?

They can only share a compromise. Cherry shrimp are listed at 6–10 dGH and crystal reds at 4–6 dGH, so the two ranges meet only at their edges, and their pH ranges overlap at pH 6.5–7.0. The care data on this site records the shared tank as a compromise for that reason. The sources also disagree on breeding risk: Shrimp and Snail Breeder says there is no hybridisation risk between Neocaridina and Caridina, while Shrimp Science claims they can interbreed near pH 7. How the pairing scores overall is explained in how scores are calculated.

Amano shrimp fit more easily with cherry shrimp than with crystal reds, because their GH ranges overlap widely. The Amano care data also notes that they are bold feeders that can outcompete slower dwarf shrimp if kept in large numbers, which is a feeding issue rather than a water one.

When does a TDS reading mislead shrimp keepers?

A TDS reading misleads when the danger is something dissolved in tiny amounts, because a meter cannot single it out. Two of the biggest threats to shrimp fall into that category.

Ammonia and nitrite

Shrimp Science advises that any trace of ammonia or nitrite is dangerous to cherry shrimp and that they belong only in fully cycled, established tanks. Traces that small may barely move a TDS reading, so a tank can read inside the target band while still being unsafe. Only an ammonia and nitrite test answers that question.

Copper

Shrimp and Snail Breeder puts the danger level for copper near 0.03 mg/L, far below the doses used in fish medications. A TDS pen cannot see that amount. Avoiding copper-based treatments, and rinsing new plants that may carry copper snail treatments, protects shrimp where a meter cannot. New plants can also carry pests such as planaria, which prey on shrimplets; the guide to planaria and hydra in shrimp tanks covers what to look for. For equipment that suits small shrimp, the comparison of sponge filters we recommend covers filter choices, and the other chemistry topics are in the water chemistry and setup guides.