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 appearing compressed or bent during molt
Visual: Unusual body position, hunched posture
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Prolonged molt attempt (normal molts take minutes)
Visual: Molt process extending over hours instead of minutes
Severe
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Shrimp trapped in old shell, unable to fully emerge
Visual: Visible gap between shell sections but shrimp stuck inside
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Shrimp with partially shed shell
Visual: Old shell partially off but still attached
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Struggling or twitching motions while molting
Visual: Shrimp flexing repeatedly but not progressing
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White ring visible around body (pre-cursor)
Visual: White band between head and tail sections
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.
Insufficient GH (Low Calcium/Magnesium)
The #1 cause of failed molts. Shrimp need calcium and magnesium to build new shells and properly release old ones. Low GH means weak new shells and brittle old shells that crack improperly.
Test GH immediately. Neocaridina need GH 6-12, Caridina need GH 4-6. If using RO water without remineralizer, GH will be near 0.
Parameter Instability
Sudden parameter changes can trigger premature molting before shrimp are physiologically ready. This includes TDS swings, temperature changes, or pH shifts.
Did you recently do a water change? Any sudden changes to the tank? Premature molts from stress are often incomplete molts.
Using Pure RO Water Without Remineralizer
Pure RO/DI water has zero minerals. Using it for water changes without adding GH+ depletes the minerals shrimp need for molting.
Are you using RO water? Do you add remineralizer? Test GH to verify mineral content.
Calcium-Poor Diet
While most calcium comes from water, diet contributes too. Shrimp fed exclusively low-calcium foods may struggle with molting, especially if water GH is borderline.
Review diet - do you provide calcium-rich foods? Blanched vegetables, cuttlebone, mineral supplements?
Very High KH with Low GH
An unusual KH:GH ratio can interfere with mineral absorption. Very high KH relative to GH may inhibit calcium uptake.
Test both GH and KH. If KH is significantly higher than GH (e.g., KH 8 with GH 2), there may be absorption issues.
Solutions
Option 1: Immediate Response (Cannot Save Affected Shrimp)
Do not attempt to manually remove the old shell - this kills the shrimp faster
- 1
Accept the shrimp cannot be saved
A shrimp in a failed molt will die. This is heartbreaking but true. Do NOT attempt to manually help them - this causes more damage and suffering.
Never try to 'help' a shrimp out of its shell - you will injure and kill them faster
- 2
Test GH immediately
Use a liquid GH test kit. This is the critical diagnostic step. Write down the value.
- 3
Test TDS, KH, and document parameters
Get a complete picture of your water chemistry. This helps identify the underlying cause.
- 4
If GH is low, begin raising it
Add remineralizer to your water change water. Raise GH by 1-2 points over several days.
Don't raise GH rapidly - increase slowly over days, not hours
- 5
Add emergency mineral source
Place cuttlebone, Wondershell, or mineral rocks in tank. These slowly release calcium while you stabilize GH.
- 6
Feed calcium-rich foods
Offer blanched spinach, kale, or commercial calcium supplements to surviving shrimp.
Recommended Products
These are informational recommendations only. Not affiliated with any brands.
Option 2: Long-term Prevention Protocol
- 1
Establish target GH based on species
Neocaridina: GH 6-8 optimal, 6-12 acceptable. Caridina: GH 4-6. Sulawesi: GH 6-8. Know your target.
- 2
Create consistent remineralization routine
If using RO water, always remineralize to target GH before adding to tank. Same brand, same ratio, every time.
- 3
Test GH weekly
Add GH testing to weekly routine. Log results to spot declining trends before they cause problems.
- 4
Maintain mineral buffer in tank
Keep cuttlebone or mineral supplement in tank permanently as a backup mineral source.
- 5
Include calcium-rich foods in diet
Regularly feed blanched vegetables (spinach, kale, zucchini), commercial shrimp foods with calcium, and occasional mineral supplements.
- 6
Avoid sudden parameter changes
Keep water changes small (10-15%), match new water parameters, and maintain stable temperature.
Prevention Tips
Follow these practices to help prevent this problem from occurring in the future.
- Maintain GH at species-appropriate levels: 6-8 for Neocaridina, 4-6 for Caridina
- Never use pure RO/DI water - always remineralize to target GH
- Test GH weekly and log results to spot declining trends
- Keep cuttlebone or Wondershell in tank as supplemental mineral source
- Feed calcium-rich foods like blanched spinach, kale, and commercial mineral supplements
- Avoid sudden parameter changes that can trigger premature molts
- Keep water changes small and consistent to maintain stability
- Use quality remineralizer with proper calcium:magnesium ratio
- Never manually intervene in a molting shrimp - let nature take its course
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 FreeMolting is one of the most critical and dangerous processes in a shrimp's life. Unlike us, shrimp have their skeleton on the outside (exoskeleton) and must periodically shed it to grow. A successful molt requires: 1. Building a complete new shell underneath the old one (requires calcium/magnesium) 2. Weakening the old shell at the split line (requires proper shell composition) 3. Absorbing water to expand and crack open the old shell 4. Wriggling out of the old shell completely 5. Hardening the new shell before predators can attack A failed molt occurs when one or more of these steps fails. The most common failure is step 1 - without adequate minerals, the new shell is too weak and malformed. The shrimp may get partway out but cannot complete the process. Once a molt has failed, the shrimp is essentially trapped in a broken shell. Their soft body is partially exposed, they cannot move properly, and they will die from the injury and stress. No amount of intervention can save them - manual attempts to 'help' only cause more tissue damage. The white ring of death is a specific type of failed molt where the shell cracks around the body circumference but the shrimp cannot emerge. It appears as a visible white band and indicates the same underlying cause: mineral deficiency. Molting frequency varies with age and conditions: - Young shrimp: Every few days to weekly - Adults: Every 4-6 weeks - Higher temperatures: More frequent molting Each molt is a risk, which is why maintaining proper GH is so critical. A single molt with inadequate minerals can be fatal.
Frequently Asked Questions
No, and you should not try. Manual intervention causes severe tissue damage and accelerates death. The shrimp's new shell is soft and connected to the old shell - pulling on the old shell tears soft tissue. The only thing you can do is let the shrimp pass naturally and focus on preventing future failures by fixing your GH.
Even with normal GH, failed molts can occur from: sudden parameter changes triggering premature molting, individual shrimp with health issues, very rapid growth in juveniles, or KH:GH ratio problems. Also verify GH is truly adequate - 'normal' varies by species. If failed molts continue, test more frequently and look for instabilities.
Young shrimp molt frequently - every few days to weekly. Adults molt every 4-6 weeks. Higher temperatures increase molt frequency. Each molt carries risk, which is why proper mineral content (GH) is critical throughout their life.
A successful molt is quick - usually completed in under a minute. You'll see the shrimp flex, the old shell splits behind the head, and the shrimp wriggles out tail-first. The empty shell remains intact and looks like a ghost shrimp. Shrimp hide after molting while their new shell hardens.
No, leave them. Shrimp and other invertebrates eat the old shells to recycle the calcium. This is natural behavior that helps maintain mineral levels. The shells will disappear within 24-48 hours as tank inhabitants consume them.
Yes. Stress from parameter changes, aggressive tank mates, shipping, or poor conditions can trigger premature molting before the shrimp is ready. Premature molts often fail because the new shell hasn't fully developed. This is why stability is emphasized as much as proper GH values.
Test your GH with a liquid test kit. If GH is below 4 for any species, or below 6 for Neocaridina, mineral deficiency is very likely the cause. If GH is adequate, look at stability - are you doing large water changes? Adding water with different parameters? Sudden changes trigger premature molts.
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.