Water parameters for Neocaridina: a practical guide

Start here: stability beats perfection

Neocaridina davidi is forgiving across a wide band of water, and much less forgiving of water that keeps moving. A colony held steadily at 9 dGH and 220 ppm TDS, a shade harder than the range below, will usually breed. The same colony, nudged towards somebody else's ideal numbers every weekend, tends to moult badly and stop breeding. Pick a target you can hit repeatedly with the water you have, then hold it.

In rough order of how much each one matters:

1. Ammonia and nitrite at 0 ppm. Nothing else matters in an uncycled tank.
2. GH (general hardness — the water's calcium and magnesium). It mineralises the new exoskeleton (the shell) at every moult.
3. Temperature stability. In late winter the live risk is cold, not heat.
4. KH (carbonate hardness). A buffer against pH swings; keepers generally find it slows pH movement more than it helps the shrimp directly.
5. pH and TDS (the acidity scale, and total dissolved solids — everything dissolved in the water). Readouts of the rest, not targets in themselves.

A working target

Parameter	Working range	Notes
GH	6-10 dGH (roughly 107-179 ppm as CaCO3)	Calcium and magnesium for moulting. Below about 4 dGH, failed moults are commonly reported.
KH	2-6 dKH	Buffering only. Opinion is genuinely divided; see below.
pH	6.8-7.8	Stability matters more than the number. Generally reported to cope up to about 8.0.
TDS	150-250 ppm	Assumes a pen using the common 0.5 (NaCl) conversion.
Temperature	Commonly kept 18-28 °C, target 20-24 °C. The outer bounds are hobby consensus rather than measured limits.	Breeding is widely reported to slow below about 20 °C.
Ammonia / nitrite	0 ppm	Generally held to be more sensitive than most community fish.
Nitrate	Under 20 ppm	Under 30 ppm is workable; many keepers report better breeding lower.
Copper	No copper-based medications; no measurable free copper	Not simply a poison: shrimp carry oxygen with haemocyanin, a copper protein, so trace copper in food and fertilisers is normal. The danger is copper-based fish and snail treatments.

GH: the one that builds the shrimp

General hardness measures the calcium and magnesium in your water, and a shrimp draws on both every time it builds a new exoskeleton. The shell is chitin (the tough material shrimp shells are built from) and protein hardened with calcium carbonate, so soft water leaves less to work with.

The failure mode is visible and fatal: a shrimp that cannot separate cleanly from its old shell gets stuck partway and dies. Hobbyists call it the white ring of death. Water too soft to build a shell is one commonly cited cause, and a sudden GH swing interrupting a moult already underway is another, but neither is settled. Nutrition, osmotic shock and bacterial infection all get blamed too. There is more in Shrimp moulting problems and the white ring of death.

Six to eight dGH covers it. Higher is not automatically better; very hard water is sometimes linked to thicker shells and harder moults, though the evidence is anecdotal. If your GH is 4 dGH or below, fix that before pH or TDS.

KH: where the hobby is divided

On KH, opinion is genuinely split, and worth reporting rather than resolving. One camp runs Neocaridina at 0-1 dKH and points to years of stable low-KH colonies. The other runs 3-6 dKH and argues that pH stability is cheap insurance, particularly for keepers not testing weekly. Both work. If you are new, 2-6 dKH is the easier place to sit.

TDS: read your own pen

Pens differ, and the difference is larger than most keepers expect. The common 0.5 (NaCl) conversion and the 0.7 (442) conversion read roughly 40 per cent apart on the same glass of water, and hobby ranges quoted online usually assume 0.5 without saying so. Use one pen and compare it against itself. What a TDS reading can and cannot tell you about the minerals actually dissolved is set out in Water parameters for Caridina and Taiwan Bee shrimp.

Temperature: the winter problem

It is late winter here, so the risk is cold. An unheated tank in a Melbourne lounge room can sit anywhere from single figures to the mid teens overnight. Neocaridina generally cope, but they will not breed well and juveniles grow slowly. Worse, it can swing several degrees between the small hours and mid-afternoon, and that movement is what causes trouble.

A small heater set to 22 °C removes the swing. Above about 26 °C dissolved oxygen falls and metabolism rises, and shorter lifespans at sustained high temperatures are widely reported, so summer needs the opposite: a fan across the surface, less light, heater off. Aim to be boring at 20-24 °C year round. Getting a colony through a cold snap, heated or otherwise, is covered in Keeping shrimp through an Australian winter.

Remineralised tap water or RO?

Both work. The question is which gives a repeatable result where you live.

Remineralised tap water means dechlorinating (removing the chlorine from) tap water and dosing a GH/KH+ mineral salt up to target. It is cheaper and faster, and sensible if your tap water is soft and consistent. Melbourne tap water is soft, reported at roughly 1-3 dGH depending on suburb and season, with TDS around 60 ppm. It is how our own Neocaridina are raised: remineralised Melbourne tap water, input TDS around 60, dosed to about 160 TDS.

RO or distilled water (RO is reverse osmosis — water purified back to almost nothing) means starting from near zero and building the water yourself. It costs more, but it takes your water authority out of the equation. Worth it if your tap water is hard or high in TDS to begin with, as reported for Adelaide and parts of Perth, or if you keep Caridina alongside Neocaridina and want one mixing procedure.

Either way, use a conditioner rated for chloramine as well as chlorine, since Australian supply areas can differ, and mix and test in a bucket first. Mix minerals in the bucket, never straight into a tank holding shrimp.

Keeping it stable in practice

The water-change routine that protects a moult, including how much to change, how often, and what to top up evaporation with, is set out in the moulting guide. The habit worth adding here is a slower one.

• Change one thing at a time. Moving from 300 ppm to 200 ppm is three or four water changes across a fortnight, not one afternoon.

When new shrimp arrive

The largest parameter change a shrimp ever experiences is the one between the bag and your tank. Drip acclimatising (introducing your tank's water a drip at a time) slowly matters more than any number in the table above, and it matters most for small juveniles: we ship unsexed juveniles (young, not yet sexable) at 0.6–1.2 cm, lively but with less margin than an adult. Our method is in the Shrimp Care and Acclimation Guide, best read before the box arrives.

Livestock ships Mondays and Tuesdays. If something does go wrong, there is a Live Arrival Guarantee: claim within 8 hours of delivery with photos and a short video of the animals in the unopened bag, and the remedy is replacement or refund of livestock value, your choice.

Get GH and temperature right, leave pH alone, use TDS as a trend line, and most of the rest follows. If you want stock already accustomed to remineralised tap water in this climate, our Neocaridina are a good place to start.