Saltwater Fish

Peppermint Shrimp

Lysmata wurdemanni

Shy night-shift shrimp hired to eat Aiptasia  ·  Intermediate

Peppermint Shrimp

Smithsonian Environmental Research Center · CC BY 2.0 — Wikimedia Commons

Lifespan
2-3 years
Adult size
4-5cm (1.5-2in)
Min. habitat
Reef 40L+ / 10gal+, stable and copper-free
Social needs
Singly or in small groups of 2-3
Diet
Scavenger (Aiptasia anemones, frozen foods, pellets)
Time
Minimal beyond reef upkeep
Cost
Low

Overview

  • 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.

Housing

  • 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.

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.

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

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