The most common question we get from new shrimp keepers is whether their tap water will do. In most of Britain the answer is yes, with one honest caveat: it depends entirely on where you live. UK tap water swings from very hard in the South East to very soft in Scotland and Wales, and that one variable decides whether you pour straight from the tap or reach for a remineraliser. This guide maps it out region by region, using the numbers Neocaridina actually care about.
Is UK tap water safe for shrimp?
For most of the country, dechlorinated tap water is exactly what our own colonies live in. Cherry shrimp are a hard-water animal at heart, and Britain's water supply suits them better than it suits half the fish people keep. There are only two things standing between your cold tap and a healthy tank, and both are easy to handle once you know they exist.
The first is chlorine or chloramine, which every UK water company adds to keep the supply safe to drink. It has to come out before shrimp go anywhere near it, every single time, and we cover exactly how below.
The second is hardness — the mineral content of your water — and this is the one that varies by postcode. Get it right and your shrimp build clean shells and moult without drama. Get it wrong, which in practice means water that's too soft, and you'll fight failed moults for the life of the tank. So before anything else, you need to know what comes out of your tap.
What shrimp actually want from your water
Here are the targets Neocaridina do best in. Hardness is the part your region decides; the rest you manage the same way wherever you live.
| Parameter | Target | What it does |
|---|---|---|
| GH (general hardness) | 6–12 | The minerals new shells are built from — the number that matters most |
| KH (carbonate hardness) | 2–8 | Buffers pH so it can't crash between water changes |
| TDS | 150–250 | Overall dissolved mineral load |
| pH | 6.8–7.6 | Tolerates 6.5–8.0 as long as it's stable |
| Temperature | 18–26°C | Room temperature is fine in most UK homes |
Of that table, GH is the one to burn into memory. It measures the calcium and magnesium your shrimp pull out of the water to harden a fresh shell after each moult, and it's the single figure that separates a region where tap water works from one where it doesn't. Every one of these parameters gets its full treatment in our Neocaridina water parameters guide; here we're only interested in what your tap delivers against them.
Reading your water company's report
Every UK water supplier publishes a water quality report by postcode, free, on their website. Search your supplier's name plus "water hardness" and enter your postcode, and you'll get the hardness for your specific supply zone. This is the ground truth for your address, and it beats any general map — including ours.
There's one catch that trips everyone up: units. Water companies almost always report hardness as milligrams per litre of calcium carbonate (mg/l CaCO3, which is the same as ppm), while aquarium test kits read in degrees of general hardness (dGH). The two measure the same thing on different scales. To convert, divide the company's ppm figure by roughly 18 to get dGH. So London's supply at around 260ppm works out near GH 14 or 15 — comfortably in the hard band.
As a rough guide to the words companies use: "soft" tends to mean under about 100ppm (below GH 6), "moderately hard" sits in the middle, and "hard" or "very hard" runs from around 200ppm (GH 11) upwards. Those labels are enough to place you, but once shrimp are in the tank we test GH ourselves with a liquid kit rather than trusting a label. Your supply can also change slightly through the year if the company blends from different sources.
The UK hardness map
Britain's water hardness follows its geology. Where the ground is chalk and limestone — most of the South and East — rain dissolves minerals on its way through and the tap runs hard. Where the ground is granite and older upland rock — the North West, Wales, Scotland, the far South West — the water picks up little and runs soft. This is the pattern in broad strokes; your postcode report always wins over the map.
| Region | Typical hardness | What it means for shrimp |
|---|---|---|
| London, South East, East Anglia | Hard to very hard, GH 12–18+ (London ~260ppm) | Pour and go — dechlorinate, no remineralising needed |
| Much of the Midlands and central England | Moderately hard to hard | Usually fine from the tap; test GH to confirm |
| North West England, the Lake District | Often soft, GH 2–6 | Remineralise up to GH 6–12 before use |
| Wales | Largely soft | Remineralise in most areas; test first |
| Scotland | Mostly soft, sometimes very soft | Remineralise; some supplies barely register on a GH kit |
| Cornwall and parts of the South West | Soft | Remineralise up to range |
Big towns don't always follow their region, because water gets piped across boundaries and blended. Manchester, for instance, draws much of its supply from the Lake District and runs soft despite sitting in England's industrial middle. That's exactly why the postcode report matters more than knowing your county.
Hard-water regions: keeping shrimp on London tap
If you're in London, the South East or anywhere the report says hard, you've drawn the easy hand. Your tap water sits at the high end of the ideal GH range or a touch above, and for Neocaridina that's genuinely fine straight from the tap once it's dechlorinated. Hard water builds good shells, and our red lines colour up beautifully on it. The classic red cherry shrimp was practically made for London tap.
The mistake hard-water keepers make is trying to fix water that isn't broken. There's a temptation to chase the textbook midpoint by cutting the tap with RO water or dosing softeners, and it almost always causes more trouble than it solves — every adjustment is one more thing to get wrong and one more source of the swings shrimp hate. Unless your GH is genuinely off the scale, well past 20, leave it alone. Dechlorinate, temperature-match, and pour.
The one number worth a glance in a hard-water area is TDS, because very hard supplies can push the upper end of the 150–250 range before you've added anything. It's rarely a problem, but it's the reason a cheap TDS pen is the first tool we recommend to anyone. There's more on reading that number in our TDS guide for shrimp keepers.
Soft-water regions: why bare soft tap fails
If you're in Scotland, Wales, Cornwall or the North West, soft tap water is the single biggest thing standing between you and a thriving colony — and it's invisible until shrimp start dying mid-moult. At GH 2–6 there simply isn't enough calcium and magnesium in the water for a shrimp to harden a new shell, so moults stall. You'll see failed moults, the dreaded white ring, and shrimp that seem to fade for no reason. It isn't your fault or theirs; it's the water.
The fix is straightforward: remineralise up to GH 6–12 before the water goes in. A shrimp-specific GH+ or GH/KH+ remineraliser is a powder you add to dechlorinated water, stirring until the TDS reads where you want it — aim for the 150–250 band and let GH land in range with it. You dose to a number, not by guesswork, which is where the TDS pen earns its keep a second time.
You've got two ways to run it. You can remineralise your own soft tap directly, which is cheapest and keeps whatever trace elements the tap already carries. Or you can start from RO or rainwater and build the water up from nothing, which gives you total consistency batch to batch — the route most serious breeders in soft regions take. Both work. Our full method, doses and the honest pros and cons of rainwater are in remineralising RO and rainwater for Neocaridina.
One warning specific to soft water: low KH usually travels with low GH, and low KH means little to no buffer against pH swings. A tank with almost no KH can see its pH crash overnight. A GH/KH+ remineraliser handles both at once, which is why we favour it over a GH-only product in the softest areas.
Dechlorinating: the step nobody skips
Wherever you live, hard or soft, every drop of new tap water gets dechlorinated first. This is not optional and it is not a step you outgrow.
Here's the part that catches people out. Old advice says to leave a bucket of tap water standing overnight so the chlorine gasses off. That worked when supplies used plain chlorine. Many UK water companies now use chloramine — chlorine bonded to ammonia — and chloramine does not gas off. It'll sit in that bucket for days, and the ammonia half is its own problem for shrimp. Standing water is not a safe shortcut anymore.
Use a liquid water conditioner that explicitly states it neutralises chloramine as well as chlorine, and add it to every batch of new water. You don't need the versions loaded with "slime coat" additives aimed at fish; a plain, honest dechlorinator that handles chloramine is all a shrimp tank wants. We keep this deliberately boring, and we've written up what to look for in shrimp-safe dechlorinators and conditioners.
What else can hide in tap water
Two other tap-water issues come up often enough to name. The first is copper, which shrimp are exquisitely sensitive to. It can leach from old copper pipework, especially from water that's been standing in the pipes overnight or in a rarely used run. If you're in an older property, drawing your tank water from the cold tap after it's run for a few seconds clears the first-draw standing water and the trace metal with it. The trace copper in a quality plant fertiliser is a non-issue; standing pipe water is the one to think about. We go deeper in copper and shrimp: the silent killer.
The second is temperature. Cold tap water in a British winter can be startlingly cold, and adding a big slug of it to a warm tank is exactly the kind of swing that triggers a bad moult. Match the new water to the tank before it goes in, and keep water changes small and regular rather than large and occasional.
Get those habits in place and, for most of the country, your tap is your friend. This whole approach folds into the wider routine in our cherry shrimp care guide, which pulls water, feeding and maintenance together into one week.
FAQ
Can cherry shrimp live in tap water?
In most of the UK, yes. Dechlorinated tap water is what our own colonies live in. Hard-water regions like London and the South East are generally fine straight from the tap once conditioned. Soft-water regions such as much of Wales, Scotland, Cornwall and the North West need a GH+ remineraliser to bring minerals up to GH 6–12. The one non-negotiable everywhere is a dechlorinator rated for chloramine.
Is London tap water OK for shrimp?
Yes. London tap water runs hard, around 260ppm or roughly GH 14–15, which sits at the high end of the ideal range and suits Neocaridina well. Just dechlorinate it and match the temperature before it goes in. Don't be tempted to soften it — hard water builds good shells, and chasing a lower GH causes more problems than it solves.
How do I know if my water is too soft for shrimp?
Test the GH with a liquid test kit, or check your water company's postcode report and convert their ppm figure to dGH by dividing by about 18. Anything under GH 6 is too soft for reliable moulting and needs remineralising up to range. Failed moults and shrimp fading mid-moult in an otherwise clean tank are the classic symptoms of soft water.
Do I need RO water for cherry shrimp?
Only in soft-water regions, and even then it's optional. If your tap is already soft you can remineralise it directly rather than buying RO. RO comes into its own when you want identical water every batch, or when your tap carries something you'd rather not dose, but hard-water keepers rarely need it at all. Neocaridina are not Caridina — they don't want soft, acidic RO water as standard.
What is the GH of UK tap water?
It ranges enormously. Hard regions like the South East run GH 12–18 or higher, while soft regions such as Scotland, Wales and Cornwall can sit as low as GH 2–4. There's no single national figure, which is exactly why you check your own postcode report rather than trusting a rule of thumb. The 6–12 shrimp want falls right in the middle of that national spread.