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Worst case: Act now5 possible causes

Shrimp are dying

Shrimp die individually or in numbers, often with no other visible problem in the tank.

Short answer

Shrimp die from things that leave fish untouched: copper, unstable hardness during moulting, and rapid parameter changes. Check what has gone into the tank before assuming disease.

Check these first, in this order

  1. What has been added to the tank in the last month — medication, plant fertiliser, snail treatment, new hardscape?
  2. Test GH and TDS. Moulting failure is a hardness problem.
  3. Was there a recent large or fast water change?
  4. Are the dead shrimp actually dead, or are they moulted shells?

Possible causes

Ordered by urgency, then by how commonly each one turns out to be the answer. The discriminator is the observation that separates this cause from the others — use it before acting.

Copper exposure

Act nowvery common

How to tell: Deaths follow a medication, a plant fertiliser, an algaecide or a snail treatment. Fish are unaffected. Copper is lethal to shrimp at concentrations harmless to fish.

Check

  • Read the ingredients of everything added recently
  • Consider new copper plumbing or a copper-containing food

Response

  • Large water changes and activated carbon.
  • Remove surviving shrimp to a clean tank if one is available.
  • Copper adsorbs to substrate and hardscape and can persist; a contaminated tank may not be usable for shrimp again without a substrate change.

    Ammonia or nitrite

    Act nowcommon

    How to tell: Shrimp are more sensitive than most fish and often die first. Testing confirms it.

    Check

    • Ammonia
    • Nitrite

    Response

    • Water change
    • Correct the underlying cause

    Failed moult from insufficient or unstable hardness

    Act todayvery common

    How to tell: Deaths cluster around moulting. A dead shrimp with a visible white line or gap across the back of the carapace — the 'white ring of death' — is the classic sign.

    Check

    • GH — below about 6 °dGH is a common threshold for problems in Neocaridina
    • Whether GH changed suddenly at a water change

    Response

    • Raise GH gradually with a remineralising product, not with a sudden addition.
    • Match water change parameters closely; drip-acclimate any change of more than a small margin.

    Rapid parameter change

    Act todaycommon

    How to tell: Deaths within hours of a water change, particularly a large one with different water.

    Check

    • Change size
    • TDS and GH of tank versus new water
    • Temperature match

    Response

    • Smaller, more frequent changes with closely matched water.
    • Add new water slowly rather than pouring it in.

    Predation rather than death

    Act within daysoccasional

    How to tell: The colony shrinks without bodies being found, and there is a fish present that eats shrimp.

    Check

    • Which fish are present and their predation risk
    • Whether shrimplets are ever seen

    Response

    • Add dense cover
    • Reconsider the tankmates if you want the colony to grow

    What not to do

    • Any medication containing copper in a tank with shrimp.
    • Assuming a moulted shell is a dead shrimp — it is translucent and empty.

    Prevention

    • Check every product for copper before it goes in.
    • Keep GH stable and adequate.
    • Match water change parameters and change gradually.