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Saltwater Fish · Shrimp
Peppermint Shrimp
Lysmata wurdemanni
Shy night-shift shrimp hired to eat AiptasiaIntermediate
- Lifespan
- 2-3 years
- Size
- 4-5cm (1.5-2in)
- Social needs
- Singly or in small groups of 2-3
- Time
- Minimal beyond reef upkeep
- Cost
- Low
- Diet
- Scavenger (Aiptasia anemones, frozen foods, pellets)
Overview
What is this animal?
- The peppermint shrimp is a small, translucent Caribbean shrimp striped in candy-cane red, bought almost exclusively for one job: eating Aiptasia, the stinging pest anemones that plague reef tanks.
- Unlike its showy cousin the skunk cleaner shrimp, it is not a dedicated fish-cleaner and spends its days wedged deep in the rockwork, emerging mostly after lights-out.
- It is cheap, peaceful, and genuinely effective pest control when you get the real thing.
- That is the catch — 'peppermint shrimp' covers a complex of near-identical Lysmata species, and shops routinely mislabel the coral-nipping camel shrimp (Rhynchocinetes) as a peppermint, so buy from a source that can tell them apart.
- The giveaway is the body and beak: a true peppermint has a slim, straight body with fine red stripes, while the camel shrimp is visibly humpbacked with a sharply upturned, hinged rostrum.
Temperament
- Peaceful toward fish, corals, snails, and other shrimp, the peppermint is a background animal rather than a pet you interact with.
- Keepers used to a bold skunk cleaner riding their hand should expect the opposite: glimpses of antennae from a cave by day and cautious foraging at night.
- It is reef-safe with an asterisk — a hungry individual may pinch food from coral mouths and occasionally pick at LPS or zoanthid polyps.
- Groups get along fine, and since they are protandric hermaphrodites any pair will produce larvae, which become live food for the fish.
- Check the stocking list both ways before buying: hawkfish, dottybacks, large wrasses, triggers, and puffers all treat a 5cm shrimp as an expensive snack.
A good fit for
- Reef keepers fighting an Aiptasia anemone outbreak
- Established, copper-free systems with stable salinity
- Budget-friendly additions to a clean-up crew
- Keepers happy with a shy, mostly nocturnal animal
- Small reefs from 40L / 10gal upward
Common mistakes to avoid
- Camel shrimp (humpbacked, hinged beak) sold mislabeled as peppermints — they nip coral
- Well-fed individuals may ignore Aiptasia entirely
- Fast acclimation — osmotic shock kills on day one
- Copper medications anywhere in the system
- Hungry shrimp picking at LPS and zoanthid polyps
- Predatory tankmates: hawkfish, dottybacks, triggers, puffers
Enclosure
Minimum 40 litres (11 US gallons)
Fine alone or with company. Singly or in small groups of 2-3
- A mature, stable reef of 40 litres (10 gallons) or more is enough for one shrimp, with plenty of rockwork caves and overhangs because this is a cryptic, nocturnal animal that needs daytime cover.
- Small groups of two or three work well in larger tanks and hunt Aiptasia more thoroughly than a lone shrimp.
- Keep salinity locked at 1.025-1.026 (about 35 ppt) and temperature at 24-26C (75-79F), with no copper anywhere in the system.
- Like all Lysmata shrimp it tolerates far less parameter swing than fish do, so sloppy top-offs and rushed water changes are the real hazards.
- Do not add it to a brand-new tank; wait until the system has been cycled and stable for a couple of months so there is biofilm and detritus to graze between meals.
Supplies
Setup
- Tank, stand and sump
- Return pump and powerheads
- Protein skimmer
- Reef lighting
- Rock and sand
- Salt mix, refractometer and test kits
- Quarantine tank
Ongoing
- Sinking marine pellets
- Frozen mysis shrimp
- Frozen chopped seafood blend
- Feeding tongs
- Turkey baster for target-feeding
- Iodine or trace-element supplement to support moulting
- Small thawing cup and strainer
Safe substrate: Aragonite sand · Dry or cured live rock · Bare bottom
Care routine
Daily
- Check salinity, temperature and flow
- Feed
- Head-count and look everyone over
- Top up evaporation with fresh water
Weekly
- Service the skimmer and filter socksevery 3 days
- Check for moults
- Clean the glass
- Test the water
Monthly
- Water changeevery 2 weeks
- Calibrate the refractometer
- Check labels for copper
- Check salt, RO/DI and reagents
Less often
- Deep-clean pumps and powerheadsevery 3 months
- Replace RO/DI filter mediaevery 6 months
Vet: Quarterly moult and stability review — every 3 months
Top resources for more info
Independent creators and organisations we would send a friend to. We have no affiliation with any of them, and nothing here is sponsored. Links checked 2026-09-19.
YouTubers
HumbleFish & ReefSaltwater fish disease, quarantine and treatment (Humble.Fish forum)BRStvReef tank setup, fish health and quarantine series (run by a retailer)FishOfHex AquaticsBeginner saltwater guides, avoiding common mistakes and tank disasters
Sites
Go deeper
Diet
- Aiptasia is the headline, and a hungry peppermint shrimp will mow down small and medium anemones, often overnight.
- Be honest about the limits: individuals vary, large established anemones are frequently ignored, and a shrimp kept well fed on easier food may never touch an Aiptasia at all.
- Beyond pest control it is a scavenger, picking over rockwork for detritus and leftovers after dark.
- Target-feed a few sinking pellets or frozen mysis a couple of times a week so it does not go hungry, but keep portions lean while an Aiptasia outbreak is being cleared.
- A genuinely underfed peppermint will start picking at easier targets, including LPS coral polyps and zoanthids, so the balance is lean feeding, not starvation.
Health
- Acclimation is the make-or-break moment, as with all ornamental shrimp: drip-acclimate over at least an hour, because osmotic shock from a quick transfer is the classic first-day killer.
- Copper-based medications are lethal to it at trace levels, so never treat the display and never reuse copper-dosed equipment.
- Regular moulting is normal — you will find a perfect ghost shell on the sand and the shrimp will hide for a day or two while its new shell hardens.
- Failed or incomplete moults usually point to unstable salinity, low calcium or magnesium, or iodine-poor water, so steady reef-standard alkalinity and mineral levels are the fix.
- Expect a working lifespan of two to three years even in a well-run tank, and factor that into how attached you get.
Is your enclosure big enough?
Minimum volume40 litres (11 US gallons)
CompanyFine alone or with company. Singly or in small groups of 2-3
Is this urgent?
In a reef, stability matters more than any single target number. A parameter moving fast does more damage than a parameter sitting slightly off.
Go now
Any detectable ammonia or nitriteWater change now with matched, mixed and aerated saltwater. Stop feeding. Directly toxic, and a marine system has less margin than a freshwater one.
NowTemperature or salinity has moved sharplyCorrect slowly, over hours, not minutes. Check the heater and the top-off. The speed of the change does the damage. Correcting fast repeats the injury in the other direction.
NowRapid gilling, or a fish hanging in the flow breathing hardIncrease aeration and check temperature and salinity. Warm water holds less oxygen, and a heater failure shows up here first.
NowToday
White spots, or a fine dusting like icing sugarIdentify which parasite before treating. Most reef tanks cannot be treated in place. The two common parasites look similar and need different handling; velvet can kill a tank in days.
TodayCorals closed for more than a day, or receding tissueTest alkalinity first, and compare it against the last reading rather than a target. Unstable alkalinity is the most commonly cited coral killer, and a swing shows up in the trend, never in a single point.
TodayA new fish added without quarantine now looks unwellRemove it to a separate system today if you can. Nearly every wipeout in a reef tank traces back to a skipped quarantine.
TodayQuarantine every new animal, including corals and inverts. It is the single practice that separates a reef that lasts from a reef that restarts.
This is general guidance for a healthy adult, not a diagnosis. An exotics vet who knows your animal always overrides it — and the time to find one is before you need one.
What it really costs
Setup, monthly, first year and across a whole life, itemised and with the electricity worked out from the actual wattage. Published figures for the same animal disagree by a factor of four, so the calculator shows ranges rather than picking one.
Bedding and substrate
In a marine system the rock and the sand are life support, and how you start them decides the first six months.
Safe
Aragonite sandThe standard marine substrate. Buffers pH and hosts the biology.
safeDry or cured live rockDry rock avoids importing pests but takes longer to mature. Cured rock is faster and riskier.
safeBare bottomCommon in high-flow systems. Easier to keep clean, but it removes a large part of the biological buffer.
safeWith a caveat
Deep sand bedsPowerful nutrient processing when they work and a sulphide release when they are disturbed. Choose shallow or deep deliberately, not by accident.
with a caveatUncured live rockIt will cycle the tank for you, and it will also bring in whatever was living in it.
with a caveatNever
Silica play sandDoes not buffer, and it is commonly blamed for feeding diatom blooms in a new tank.
neverAny rock or decor of unknown originMetals and phosphate leach for months and are almost impossible to trace once the tank is running.
neverThis is our general list for saltwater fish. We have not built one specific to Shrimp yet.
My kit says 0.25 ppm. Is that dangerous?
A liquid kit measures total ammonia, but only the un-ionised fraction is really toxic, and that fraction is governed by pH and temperature — each whole pH unit multiplies it roughly tenfold. So the same reading can be nearly harmless in one tank and lethal in another; this works out which one you are in.
Compare with other animals
The same axes for every animal, side by side — the way the guides are written makes that a fair comparison rather than two articles.
Keep going
Shrimp, side by side
Same axes, same care guides — the honest way to choose between types.
See all Shrimp side by side →
