Shrimp water changes: how much and how often

The short answer

Shrimp are sensitive to fast change, not just to the numbers on a test kit. A routine of small, regular changes keeps waste down without shocking the colony, and the water you add should look as much like the tank as you can make it.

Step by step

1. Treat the new water every time

San Diego tap is chloraminated, and chloramine does not gas off in a bucket. Use a conditioner that neutralizes chloramine, or a carbon filter rated for it, on every batch you add. For Caridina, mix remineralized RO water to the same TDS as the tank instead.

2. Match temperature and TDS

Warm the new water to within a degree or two of the tank and check that its TDS is close to the tank reading. Shrimp react to the speed of change more than to the values themselves, so a mismatch is the usual cause of trouble after a water change.

3. Change a small amount

Ten to fifteen percent once a week is plenty for a lightly stocked tank. Smaller, regular changes are safer than a big change now and then. Skip the change if the tank is stable and healthy and you cannot match the water.

4. Add it slowly

Run the new water in gently, ideally as a slow drip or along the glass, so the shrimp are not hit with a sudden shift in temperature or chemistry and the substrate is not stirred up.

5. Siphon gently and leave the biofilm

Take water from over the substrate or from where debris collects, and keep the siphon away from shrimplets and moss. Do not scrub the glass, decor or filter sponge clean, because biofilm is food.

Neocaridina and Caridina

Neocaridina tolerate dechlorinated San Diego tap water, which is hard (the City of San Diego 2025 report gives GH of about 13 and TDS of roughly 530–590 ppm). If your tank runs at a different TDS, bring the new water close to it rather than switching suddenly. Caridina need soft, acidic, low-TDS water, so they are never changed with tap: use remineralized RO water mixed to the tank’s own reading. See water parameters and San Diego tap water for shrimp for the numbers.

When to skip or change more

If shrimp are mid-molt, newly added or the water you have does not match, waiting a few days costs little. If ammonia or nitrite is above zero, or the water smells, a change is worth doing, but keep it small and repeat rather than swapping a lot at once. Overfeeding is a common reason a tank needs rescuing; see how to feed shrimp.

Questions we get asked

How often should I change water in a shrimp tank?

A small change once a week is a common routine for a lightly stocked, established tank. A tank that is stable and not overfed can manage with less. Test ammonia and nitrite if shrimp seem off, and change water if they read above zero.

How much water should I change?

Ten to fifteen percent is plenty for most shrimp tanks. Avoid large changes unless you are fixing a problem, and even then match temperature and TDS as closely as you can.

Can I use San Diego tap water for water changes?

For Neocaridina and Amano, yes, once it has been treated with a conditioner that neutralizes chloramine. Letting a bucket stand does not work because chloramine does not evaporate. Caridina need RO water remineralized for them instead. See the San Diego tap water guide.

Why did my shrimp die after a water change?

The usual causes are untreated chloramine, a large swing in temperature or TDS, or a conditioner or additive that was overdosed. Molting shrimp are especially sensitive. If you lose shrimp after a change, stop changing water, test the tank and compare the new water's TDS and temperature before the next change.

Should I clean my filter at the same time as a water change?

Not both at once if you can help it. The filter holds the bacteria that process ammonia. If it needs cleaning, rinse the sponge gently in water taken from the tank, never untreated tap water.

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