The Four Numbers Every Neocaridina Keeper Must Know
Neocaridina shrimp are forgiving compared to Caridina species, but they still have clear preferences that significantly impact survival and breeding. The four parameters to monitor are: GH (general hardness, measuring calcium and magnesium), KH (carbonate hardness, measuring buffering capacity), pH (acidity/alkalinity), and TDS (total dissolved solids, an overall measure of mineral content). Understanding what each number means and how they interact is the foundation of successful shrimp keeping.
GH for Neocaridina should sit between 6 and 10 dGH. This range supplies sufficient calcium for regular, successful molting and enough magnesium for enzymatic processes. Too low (below 4 dGH) and shrimp will suffer failed molts; too high (above 14 dGH) and the water becomes uncomfortably hard, stressing the animals over time. KH should be in the 2–5 dKH range. Higher KH stabilizes pH but also raises it — a KH above 8 will push pH above 8.0, which is the upper limit of what Neocaridina tolerates well.
TDS is a useful quick-check parameter. Neocaridina are happy between 150 and 250 ppm TDS. A TDS pen is inexpensive and fast — if TDS is within range, the other parameters are likely close to acceptable. pH should be between 6.8 and 7.5. In practice, anything from 6.5 to 8.0 is survivable, but the sweet spot of 7.0–7.4 produces the best breeding rates. In Cambodia's climate, aim for 22–26°C water temperature, using a fan evaporative cooler if ambient temperatures push above 30°C.
- ✦Buy a TDS pen (available for under $5 USD in Cambodia electronics markets) — it gives you an instant health snapshot of your water
- ✦Test GH and KH monthly using a liquid test kit; API GH/KH kit is accurate and available through Phnom Penh aquarium suppliers
- ✦Keep a water parameter log with dates — spotting trends early prevents shrimp deaths before they happen
Cambodia Tap Water — Challenges and Solutions
Tap water quality in Cambodia varies significantly by city and even by neighborhood. Phnom Penh municipal water is treated with chlorine and sometimes chloramine, both of which are acutely toxic to shrimp at any concentration. Always dechlorinate tap water before use — sodium thiosulfate dechlorinators (sold as "water conditioner" at aquarium shops) neutralize chlorine instantly, but chloramine requires a conditioner that also neutralizes ammonia (look for products containing sodium thiosulfate plus a binder like Prime by Seachem).
Beyond treatment, Cambodia tap water tends toward either very soft (low GH, low KH) or moderately hard depending on the source. In areas served by surface water, GH can be as low as 1–3 dGH, which is insufficient for shrimp molting. In areas with groundwater influence, GH may be higher but sometimes comes with high iron content that discolors the water brown. Testing your specific tap water is essential before building your shrimp parameters strategy.
In rural Cambodia, well water is common and can be either excellent or problematic. Some wells produce soft, slightly acidic water that is ideal for shrimp after simple GH supplementation. Others contain high concentrations of iron, arsenic, or hydrogen sulfide that require filtration beyond standard dechlorination. If you are in a rural area, have your water tested at an agricultural testing lab or a university lab before investing heavily in a shrimp colony.
- ✦Let dechlorinated tap water sit in a bucket for 24 hours before adding it to shrimp tanks — this off-gasses dissolved CO2 and stabilizes pH
- ✦Keep a 5-liter batch of pre-treated water always ready so emergency water changes are possible without harming shrimp
- ✦In Phnom Penh, water quality often changes with the seasons (dry vs rainy) — re-test your tap water at the start of each season
Using RO Water for Perfect Neocaridina Parameters
Reverse osmosis (RO) water is essentially pure H2O with all minerals removed — a blank canvas you can build to exact specifications. Many serious Neocaridina keepers in Cambodia and across Southeast Asia have switched to RO water because it eliminates the uncertainty of tap water quality entirely. An RO unit can be purchased for $50–120 USD and produces water at roughly 1–5 ppm TDS, far below the 150–250 ppm target for Neocaridina.
To use RO water for Neocaridina, you must remineralize it using a GH booster. Products like Salty Shrimp GH+ are specifically formulated for Neocaridina — they add calcium, magnesium, and potassium in the correct ratios to reach your target TDS without raising KH unnecessarily. The typical dosage to reach 200 ppm TDS varies by product, so follow the manufacturer's chart and verify with a TDS pen before each water change.
A practical approach for Cambodian hobbyists without an RO unit is to blend tap water with purchased RO or distilled water (sold at water stations throughout Cambodia for approximately 500–1000 KHR per liter). By mixing 50% tap with 50% RO/distilled, you dilute chlorine, reduce TDS, and soften the water, then remineralize to target. This is more affordable than full RO for small tanks and produces excellent results for Neocaridina.
- ✦Use Salty Shrimp GH+ or equivalent Neocaridina-specific remineralizer — never use marine salt or Caridina-specific products for Neocaridina
- ✦Mix RO/distilled water and GH booster in a bucket first, verify TDS with your pen, then add to the tank slowly over 30 minutes
- ✦Water station RO water (sold throughout Cambodia) is a budget-friendly alternative to buying a home RO unit for tanks under 40 liters
Copper Toxicity — The Silent Shrimp Killer
Copper is lethal to all invertebrates, including shrimp, at concentrations as low as 0.01–0.1 ppm. This is well below the level harmful to most fish, which means a copper-treated fish tank is potentially lethal to shrimp even after the apparent treatment period. Copper accumulates in substrate and decorations and can leach back into the water for months after treatment. Never add shrimp to a tank that has been treated with copper-based medications without first replacing all substrate and rinsing all decorations thoroughly.
Copper also enters aquariums through tap water. Old copper pipes in buildings — particularly in older Phnom Penh structures — can add measurable copper to tap water, especially if the water sits in the pipes overnight. The so-called "first flush" from a tap that has been idle for hours may contain elevated copper. To test this, run the tap for 30 seconds before collecting water, or use a copper test kit available from aquarium suppliers.
Some plant fertilizers and root tabs contain copper as a micro-nutrient for plant growth. Read labels carefully and avoid any liquid fertilizer that does not explicitly state it is shrimp-safe. Products from Seachem (Flourish Comprehensive) do contain trace copper but at levels tolerated by established shrimp colonies in larger tanks; in nano shrimp tanks, opt for fertilizers marketed specifically as shrimp-safe or copper-free.
- ✦Test tap water for copper if you live in a building with old pipes — run the tap 30 seconds before collecting water for shrimp tanks
- ✦Never use copper-based anti-algae treatments or fish medicines in a tank that contains shrimp or snails
- ✦When buying liquid fertilizer, check the label for copper content — use only shrimp-safe fertilizers in tanks under 30 liters
Performing Water Changes Without Stressing Shrimp
Water changes are essential for removing nitrates and replenishing trace minerals, but done incorrectly they are a major source of shrimp stress and loss. The key rules are: match the temperature of new water to tank water within 1°C, never change more than 20–25% of the tank volume at once in a shrimp-only tank, and always add new water slowly using a drip method or by pouring over a sponge to dampen the flow.
In Cambodia's warm climate, tap water from the tap may actually be close to room temperature, but on cooler evenings during the dry season (November–February) the difference can be enough to shock shrimp. Always use a thermometer to verify. Additionally, water changes should be performed at consistent times — weekly is ideal. Irregular water changes that go from three weeks without a change to a 30% change all at once are highly stressful to shrimp colonies.
During the first three months of a new shrimp colony, reduce water change frequency to once every two weeks and keep volume at 15% maximum. During this establishment period, the colony is building its beneficial bacteria layer and adjusting to the new tank environment. Large, frequent water changes during this period disrupt the cycle and cause unnecessary deaths. Once the colony is breeding and juveniles are visible, you can begin a regular weekly schedule.
- ✦Use a drip line (airline tubing with a knot to slow flow) when adding new water — aim for no faster than 1 liter per 5 minutes for nano tanks
- ✦New water must be dechlorinated AND temperature-matched — a 3°C difference is enough to trigger a stress molt in sensitive individuals
- ✦Mark a water change schedule on a calendar and stick to it — consistent small changes outperform irregular large ones every time