Symptoms to Look For
Check if your shrimp are showing any of these symptoms. Symptoms are grouped by severity to help you assess the situation.
Moderate
-
Shrimp swimming erratically immediately after water change
Visual: Darting, hitting glass, frantic swimming behavior
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Shrimp becoming lethargic after water change
Visual: Hiding, not grazing, staying motionless
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Shrimp gasping near water surface after change
Visual: Indicates chlorine or oxygen issues
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Berried females dropping eggs after water change
Visual: Stress response to parameter shift
Severe
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Deaths occurring 1-48 hours after water change
Visual: Timeline clearly correlates with water change event
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Multiple shrimp dying but fish are fine
Visual: Shrimp more sensitive than fish to parameter swings
Does this match what you see? If your shrimp are showing multiple severe symptoms, act immediately. Early symptoms give you more time to correct the issue.
Possible Causes
Causes are listed by likelihood. Start with the most common causes and work your way down.
TDS Shock (Osmotic Stress)
The most common cause. If new water has significantly different TDS than tank water, shrimp experience osmotic stress as water moves in/out of their cells. Even a change of 30-50 TDS can be stressful; larger swings can be fatal.
Test TDS of your tank water and your prepared water change water. Difference greater than 20-30 ppm is risky.
Chlorine or Chloramine in New Water
Tap water contains chlorine (evaporates) or chloramine (does NOT evaporate) to kill bacteria. These chemicals are lethal to shrimp. Chloramine requires specific treatment.
Did you use dechlorinator? Does your water company use chloramine? Check their water quality report or call them. If you let water 'sit out' but didn't use dechlorinator, chloramine is still present.
Temperature Mismatch
Adding water that's significantly colder or warmer than tank water causes temperature shock. Shrimp are ectothermic and rapid temperature changes affect their metabolism and immune system.
Did you match water temperature? Use a thermometer to compare new water to tank water. Difference greater than 2-3F is stressful.
pH Swing
Adding water with significantly different pH causes stress. This is especially common when using tap water with different pH than established tank, or when CO2 injection affects pH.
Test pH of both tank and new water. Swings greater than 0.3-0.5 pH units are stressful.
Water Change Too Large
Even if parameters match perfectly, very large water changes (50%+) cause stress simply from the disturbance and minor parameter shifts. Shrimp thrive on stability.
What percentage did you change? Changes over 25-30% at once are risky even with matched parameters.
Copper in Source Water
Some tap water contains trace copper from pipes, treatment plants, or seasonal variations. Copper is lethal to shrimp even in tiny amounts.
Test source water for copper. Check if your home has old copper pipes. Note if deaths only happen with tap water changes.
GH/KH Crash After Change
If using softer water for changes, GH and KH drop, potentially triggering premature molts or mineral deficiency stress.
Test GH and KH before and after water change. Drops of more than 2-3 degrees are concerning.
Solutions
Option 1: Immediate Response After Problematic Water Change
Additional water changes will compound the stress - resist the urge to 'fix' immediately
- 1
Do NOT do another water change
If shrimp are already stressed, another water change will cause additional shock. Wait and let them stabilize unless ammonia/nitrite is elevated.
The instinct to 'fix' with another change often makes things worse
- 2
Test current tank parameters
Test ammonia, nitrite, pH, TDS, and temperature. Document these values to understand what changed.
- 3
Add extra aeration
Increase surface agitation or add an airstone. Stressed shrimp need more oxygen, and if chlorine is present, aeration helps dissipate it.
- 4
Add activated carbon if toxin suspected
Fresh activated carbon can absorb chlorine, chloramine byproducts, and other potential toxins.
- 5
Wait 24-48 hours before any intervention
Allow surviving shrimp to stabilize. Monitor for additional deaths but avoid making more changes.
Recommended Products
These are informational recommendations only. Not affiliated with any brands.
Option 2: Safe Water Change Protocol (Prevention)
- 1
Prepare water 24 hours in advance
Fill a container with your water change water, add dechlorinator, and let it sit to reach room temperature. Add remineralizer if using RO.
- 2
Match TDS within 20 ppm of tank
Test tank TDS, then adjust your change water with RO or remineralizer until it matches within 20 ppm.
- 3
Match temperature within 2F
Use a thermometer to verify. If water is cold, let it warm to room temp or use an aquarium heater in the bucket.
- 4
Add water slowly
Use airline tubing to drip water in, or pour very slowly. Fast addition creates localized parameter pockets.
- 5
Keep changes to 10-15% weekly
Smaller, frequent changes are much safer than large, infrequent ones. Some keepers successfully do 5% twice weekly.
Prevention Tips
Follow these practices to help prevent this problem from occurring in the future.
- Always use a dechlorinator that treats both chlorine AND chloramine (like Seachem Prime)
- Match new water TDS within 20 ppm of tank water before adding
- Match temperature within 2F (1C) of tank water
- Keep water changes small: 10-15% weekly maximum, or 5% twice weekly
- Prepare water change water 24 hours in advance when possible
- Add new water slowly - drip or pour very gradually over 10-15 minutes
- Test your source water periodically as municipal water chemistry can change seasonally
- If using RO water, always remineralize to appropriate GH before use
- Consider using an old tank or bucket as a dedicated water aging container
- Avoid water changes when you have berried females approaching egg release
Related Parameters to Monitor
Track These Parameters with ShrimpKeeper
Get alerts when your parameters drift out of range, see historical trends, and catch problems before they become emergencies.
Download FreeWater changes are essential for maintaining water quality, but they're also the #1 cause of preventable shrimp deaths. Understanding why helps prevent disasters. Shrimp are incredibly sensitive to parameter changes because they absorb water and minerals directly through their gills and shell. When water parameters change suddenly, the osmotic balance is disrupted - water may rush into or out of cells, minerals may shift, and the shrimp's entire physiology is stressed. TDS (Total Dissolved Solids) is the most critical parameter to match during water changes. TDS measures everything dissolved in water - minerals, salts, organics. When new water has very different TDS, water moves across cell membranes to equalize concentration. This osmotic stress can damage organs and is often fatal. For example: Tank water at 180 TDS, new water at 100 TDS = immediate 80 ppm swing. Even though both numbers seem 'OK' individually, the sudden change is the problem. Shrimp are adapted to their current TDS and cannot rapidly adjust. Chlorine and chloramine are the other major killers. While fish can sometimes tolerate brief chlorine exposure, shrimp cannot. Chloramine is particularly dangerous because unlike chlorine, it does not dissipate by letting water sit out. You MUST use a dechlorinator that specifically treats chloramine. The safest approach is making water changes boring and predictable. Same amount, same day each week, same water preparation process. Stability is what shrimp crave.
Frequently Asked Questions
Shrimp are far more sensitive than fish to parameter changes, especially TDS and chlorine. Fish have more robust osmoregulation and can tolerate swings that would kill shrimp. A water change that's 'fine' for fish may be fatal for shrimp. Always match parameters more precisely for shrimp tanks.
Wait at least 1-2 weeks if losses were significant, allowing survivors to fully destress and stabilize. When you do resume, change your method: prepare water in advance, match TDS precisely, and do a much smaller change (5-10%). Test parameters before and after to verify stability.
10-15% weekly is the generally recommended maximum, with many experienced keepers preferring 5-10% twice weekly. The key is consistency and proper parameter matching. Never exceed 25-30% at once, even in emergencies, as the parameter swing can be worse than the original problem.
Dripping is ideal but not strictly necessary if parameters are well-matched. The benefit of dripping is gradual introduction that allows shrimp to adjust. If you've matched TDS within 20 ppm and temperature within 2F, you can pour slowly without dripping. But if parameters don't match well, dripping helps reduce shock.
No. Chlorine will dissipate from water left to sit (24-48 hours), but chloramine does NOT. Chloramine is chlorine bonded to ammonia and remains stable in water. You must use a dechlorinator that specifically treats chloramine (like Seachem Prime). Check with your water company if unsure which they use.
No - water changes are necessary for removing nitrates and replenishing minerals. The solution is not to stop changes but to do them properly. Prepare water in advance, match parameters precisely, keep changes small and frequent, and use quality dechlorinator. Properly executed water changes are safe.
Water changes can trigger molting in shrimp. If a berried female molts, she loses the eggs attached to her swimmerets. This is usually caused by TDS or temperature shock triggering a premature molt. Avoid water changes when you have berried females near the end of their gestation (around 25-30 days), or make changes extra small and gentle.
Track Your Parameters with ShrimpKeeper
Most shrimp problems stem from parameter issues. Track your water quality, get alerts when things drift, and prevent problems before they happen.