Pederson Cleaner Shrimp – Detailed Guide: Care, Diet, and Breeding

Pederson Cleaner Shrimp (Ancylomenes Pedersoni)

Although Pederson Cleaner Shrimps (Ancylomenes Pedersoni) are not that common in the aquarium trade, they will certainly add some variety to your marine habitat. So, if you have you been thinking about keeping these shrimp, but you aren’t sure how to care for them or you just what to learn more about this species. Then you’ve come to the right place.

In this guide, I will discuss Pederson Cleaner shrimps appearance, behavior, dietary needs, tank conditions, ideal tank mates, breeding and much more.

Right from the start, I would like to say that, in general, Pederson Cleaner Shrimps are peaceful, relatively easy to keep and care for. They are one of the best fish cleaners, good scavengers and can be a part of a group of animals in a reef aquarium, “cleaning crew”.

Keep reading for everything you need to know about them!

Quick Notes about Pederson Cleaner Shrimp

Name Pederson Cleaner Shrimp
Other Names
Anemone Cleaner Shrimp, Anemone Shrimp, Caribbean Anemone Shrimp, Carid Shrimps, Cleaner Shrimp, Commensal Shrimps, Pederson’s Shrimp, Symbiotic Cleaner Shrimp
Scientific Name Ancylomenes Pedersoni (previously Periclimenes pedersoni)
Tank size (minimum) 5 gallons (~20 liters)
Keeping Easy
Breeding Moderate-Difficult 
Size up to 2.5 cm (~1 inch)
Optimal Temperature 22 – 26°C  (~72°F – 79°F)
Water type SG = 1.021 – 1.025
Optimal PH 8.1 – 8.4
Optimal KH 7 – 12
Nitrate Less than 20 ppm
Diet Omnivore / Carnivore 
Temperament Peaceful
Life span up to 1.5 years
Color Form Translucent with blue spots

Natural Habitat of the Pederson Cleaner Shrimp

Pederson Cleaner Shrimps occur in tropical waters from Cape Lookout, North Carolina, down the east coast of the United States and around the west coast of Florida, to the Bahamas, West Indies, Bonaire, Netherland Antilles, and Belize.

They can be found in coral reef systems (at depths of 1 to 15 meters (3 to 49 ft), where they also establish a cleaning symbiotic relationship with fishes, removing parasites, bacteria, and damaged tissues. 

Description of the Pederson Cleaner Shrimp

Pederson Cleaner Shrimp (Ancylomenes Pedersoni)Pederson Cleaner shrimp is an interesting ornamental shrimp known for its whole-body transparency. At rest, under normal conditions, Ancylomenes pedersoni are transparent enough to read the text through its body. These shrimp have translucent bodies covered with blue points and white stripes that run from the head to the tail and claws.

These shrimp are easy to distinguish due to several identifying features on their bodies, such as very long slender pincers (2/3 of the body length) and a distinctive hump that looks very similar to Camel shrimp (Rhynchocinetes  durbanensis).

Pederson Cleaner shrimp can grow up to 2.5 cm in length (~1 inch). These small shrimp have a very fast metabolism and do not live more than 1.5 years for females and slightly more than 1 year for males. 

Interesting fact: according to the experiments, exercise, salinity, and small injuries will temporarily disrupt transparency of the Pederson Cleaner shrimp.

For example, according to the experiment, eliciting additional tail flips to the point of exhaustion (16 – 20 times) resulted in complete opacity, though the original transparency returned after 20–60 min of inactivity. In addition, when also became opaque in fewer than 2 min in hyposaline (8‰) and hypersaline (55‰) water. However, they recovered transparency within 10 minutes.

The Behavior of the Pederson Cleaner Shrimp 

Pederson cleaner shrimp, as the name suggests, is mainly known for its cleaning properties as it can clean parasites from fish skin, and even the mouth of a large fish like grouper.

Although this species is very versatile, and, in nature, they were found alone, in pairs, or in groups of 5–6 individuals. It is still recommended to keep several shrimps in the tank. Given a choice, they tend to aggregate in groups potentially reflecting the small size and limited defensive capability of these shrimps.

Pederson cleaner shrimp are completely peaceful. They do not seem to care about anything else in the tank but cleaning and scavenging.

Unlike some shrimp species, they are not territorial and males will not fight. Additionally, males Ancylomenes Pedersoni do not exhibit sexually selected traits, including exaggerated weaponry or robust body shapes, that would aid in competition with other males.

Despite their size, these shrimp are not very shy. Pederson cleaner shrimp are also associated with anemones, which they use as the cleaning stations.

Interesting Fact: Pederson Cleaner Shrimp as Cleaner

Pederson cleaner shrimps (Ancylomenes pedersoni) are major cleaners (even more so than do cleaner fishes!) of reef fishes in the tropical western Atlantic and form obligate symbioses with host sea anemones. Cleaner organisms are ecologically important on coral reefs, in that they remove parasites and potentially enhance the healing of surface wounds on client fish.

They remove cymothoid isopods from fish clients and significantly reduce the abundance and size of monogenean parasites on fish.

According to the observations, clean durations ranged from a few seconds up to 11 minutes, but most cleans lasted 20 seconds. The time of cleaning also depends on the fish, for example, lizardfish and groupers received the longest cleans.

There are at least 22 fish species that use cleaning service including Aulostomidae (trumpetfish), Balistidae (triggerfish), Bothidae (left-eye flounders), Muraenidae (moray eels), Pomacanthidae (angelfish) and Tetraodontidae (puffer fish).

Cleaning stations are spatially and temporally dynamic on coral reefs because cleaner shrimps may migrate nocturnally among host anemones and some host anemones have short life spans.

Pederson Cleaner Shrimp and Anemone Partnership

The Pederson cleaner shrimp is a symbiotic cleaner shrimp. They frequently associate with Bartholomea annulata, to a lesser extent with Condylactis gigantea, and occasionally with other anemones (for example, sun anemones Stichodactyla helianthus, etc.) which they use as the centers of cleaning stations that attract client fishes for ectoparasite removal. In addition, these shrimp clean the anemone removing organisms caught in the anemone’s mucus.

Because of their ability to host cleaners and act as visual signals that draw in client fishes, the anemones also can receive nutrients in the form of waste products (excreted ammonia and eliminated feces) from their crustacean symbionts and visiting clients, thus contributing to efficient nutrient cycling on coral reefs. 

Pederson shrimps also do not exhibit fidelity to a single species of host sea anemone and have the ability to migrate and acclimate to several types of reef anemones.

Note: Keep in mind that Pederson shrimp will need time to acclimate itself to the anemone in your tank by progressively pressing its body against the tentacles of the anemone. So, if you separate them from its host, they will have to re-acclimate themselves to that anemone once again.

Are Pederson Cleaner Shrimp Coral Safe?

Yes, you should not have any problems with Pederson cleaner shrimp in reef tanks. I have not heard any reports that they eat SPS frags, destroy polyps or something like this.  

Feeding Pederson Cleaner Shrimp

Although these shrimp feed on parasites and dead skin on client fish as well as detritus. It does not mean that there is no need to feed them. The idea that they can survive off the parasites and leftovers from feeding community fishes is bad.

The reason is that Pederson cleaner shrimp can start cheating client reef fishes and pick up healthy skin, scales and mucus at the painful expense of their clients or try to steal all the food from the corals. Therefore, you need to provide them some food at least 2 – 3 times a week.

Pederson cleaner shrimp are omnivore. They will eat any pellet, flake, and gel foods that provide animal-based nutrition. Meaty food with higher fat/protein content can accelerate growth and breeding. Basically, the diet should be comprised of meaty seafood or marine flake food.

Note: As an example,  in the experiments, biologists fed them every other day to saturation with fish food pellets (links to check the price on Amazon):

which caused them to grow rapidly, up to 2 mm carapace per month. 

Keeping and Caring for Pederson Cleaner Shrimp

Keeping Pederson cleaner shrimp in an aquarium is not difficult because they do not have special water quality requirements. Therefore, keeping them alive and well in your tank should not be a problem.

Tank Size:

Being somewhat small, Pederson cleaner shrimp do not need a substantial amount of space in the aquarium. Therefore, Nano reef tanks can be a good choice for these shrimp.
Note: Although Pederson cleaner shrimp are pretty resilient as aquarium inhabitants, they survive better in smaller tanks with less flow because they were less likely to become sucked into sumps.

Water Requirements:

The temperature should stay in the range of about 72 to 79 F (22 to 26 C) with around 75 to 77 (24 – 25C) being optimal. The salinity should be in the range of 1.021 – 1.025 as measured using its specific gravity.

Keep the concentration of calcium in the range of 400 to 450, the PH around 8.1 to 8.4  and the alkalinity of the aquarium’s water in the range of 7 to 12 dKH.

Hiding places:

Your tank should have plenty of rocks and caves for your crab to hide in. This is crucial for their well-being.

Note: Consistent water parameters are the cornerstone of any successful aquarium.  Make sure that they are all kept within a suitable range (at all times) and do not jump around.

Important: Before putting the Pederson cleaner shrimp in your tank do not forget to acclimate it (read more about it) as all invertebrates.
Be careful with chemicals like copper (read more). Crabs, shrimp, and crayfish do not tolerate copper-based medications or fluctuating water parameters.

Basic Tank Equipment (links to check the price on Amazon)

Sexing Pederson Cleaner Shrimp

It can be difficult to sex them unless you know the age of the shrimp. The point is that at the same age:

  1. Size. Females are bigger compared to males. Most females attained a maximum body size of ~2.5 cm (1 inch). In contrast to females, males never attain that size class, reaching maximum body sizes of only ~2.0 cm (0.8 inches).
  2. Color. This is another way to distinguish between male and female. Females of Pederson cleaner shrimp are more colorful.
  3. Body structure. Males have a narrow body. Females tend to have bigger and rounder underbelly (abdomen) whereas the males do not have a curved abdomen.

The more reliable indicator of gender is the presence of what is known as the saddle (beige oocytes visible in the cephalothorax). The saddle consists of small undeveloped and unfertilized eggs forming in the female’s ovaries. If you can see a saddle. You can be 100% certain you are looking at a mature female.

Pederson Cleaner Shrimp and Molting

Like with all crustacean, Pederson cleaner shrimp need to molt (shed their old exoskeleton – read more about it) to grow. After shedding, when the body is still soft and flexible, they start pumping their bodies with water, thus increasing it in size.  

Molting is the most important and most dangerous process in their lives. Without hard exoskeleton, they are extremely vulnerable. Therefore, it is crucial to your shrimp survival that your tank has plenty of hiding spaces. They will choose one of these spaces as a safe retreat while they are weak.

Depending on the age of the shrimp, they can molt every week as juveniles or every 2 – 3 weeks as adults. The molt interval is several days longer in females than in males.

If you see that Pederson cleaner shrimp changed in body color from mostly transparent to opaque without any obvious reason, it can mean that the shrimp is preparing to molt. It occurs 1 – 2 days prior to each molt.

Tip: Do not remove the old exoskeleton. It contains a lot of calcium and your shrimp will gladly eat it later.

Note: Like all invertebrates, Pederson cleaner shrimp need calcium to mineralize (harden) the shell.  Calcium is vital for good shell growth. I highly recommend reading my article “How to Supplement Shrimp and Snails with Calcium”.

Mating and Breeding Pederson Cleaner Shrimp

This species reaches sexual maturity at ~6 months.

Female molts prior to mating and release a certain chemical substance into the surrounding water to attract males. This signals the male that the female is ready to spawn.

After the mating process, the eggs become fertilized when they pass through the seed on the way to the brood pouch. The pouch is formed by pleopods and overhanging of pleura of the female. Fertilized eggs are yellowish in color.

Each female usually carries from 20 – 60 eggs. The incubation period of developing embryos ranges from 14 to 20 days. The egg increase during development, this is a result of water uptake. The increase in egg volume caused by water uptake limits the availability of egg carrying space, resulting in smaller broods but this is normal.

Pederson Cleaner shrimp embryos hatch as pelagic larval form. 

Pederson Cleaner Shrimp and Suitable Tank mates

Although Pederson shrimps are cleaning organisms and thus are largely immune to predation by reef fishes, which visually recognize the status of cleaners and avoid consuming them, I would not advise to keep them in the aquarium with big and predatory fish anyway.

In nature, these fishes suppress their hunting instinct to get an even better result – being clean and healthy. However, in aquariums, it may not work that well. Constant close contact between cleaner shrimp and dangerous clients can end up being eaten by a number of carnivorous fish species.

Pederson cleaner shrimps are very peaceful and due to their small size, they are practically defenseless. Because of this, they are only suited to the most docile environments.

They get along well with others of its kind, so maintaining a group is not problematic but it will require more space.

Good tank mates for Pederson shrimps:

If you have Emerald crabs and Red Fire shrimp I would just be careful and watch them closely (especially with big crabs and territorial shrimp).

Do not keep them with Arrow crabs and Coral banded shrimp. As they will likely begin to prey on them eventually.

Do not keep them with Clownfish. These fishes will not tolerate Pederson shrimps in their anemone and bully them to get anemone for themselves. 

Some Facts about Aging Pederson Cleaner shrimp

In Pederson Cleaner shrimp, aging is characterized by up to 5 processes observed during 1–4 weeks prior to natural death:

  1. Body shrinkage. They become a little smaller with a decrease in wet mass.
  2. Change in body color from mostly transparent to opaque. It can start and last up to 1 – 2 weeks during aging.
  3. Reduced activity level. They become slower, do not display cleaner signaling behaviors, stop interacting with other shrimps,
  4. Reduced feeding.
  5. Reduced or ceased sexual reproduction.

According to the reports, the most commonly observed senescence processes involved changes in body color from mostly transparent to opaque and changes in behavior including reduction of food consumption. Other processes were observed only occasionally because they occurred mostly in females and required frequent monitoring to detect, including body shrinkage in very large females (detectable only through monthly size measurements) and cessation of sexual reproduction

In Conclusion

Many saltwater shrimp have been gaining popularity in the marine aquarium industry over the past years and Ancylomenes Pedersoni is one of them. Pederson Cleaner Shrimp are easy to care for. They are hardy, reef-safe and interesting to watch. In addition, they are great fish cleaners, excellent scavengers and ideal members of any clean up crew. 

All these qualities make them a wonderful addition to any marine tank. 

References:

  1. Transparent anemone shrimp (Ancylomenes pedersoni) become opaque After exercise and physiological stress in correlation with increased hemolymph perfusion. Journal of Experimental Biology. (2017) 220, 4225-4233 doi:10.1242/jeb.162362.
  2. Life-History Traits and Population Structure of Pederson Cleaner Shrimps Ancylomenes pedersoni. Department of Biological Sciences, 101 Rouse Life Sciences Building, Auburn University, 233: 190–205. (December 2017).
  3. Ecological traits of Caribbean sea anemones and symbiotic crustaceans. Marine Ecology Progress Series. 2012 DOI: 10.3354/meps10030.
  4. Host selection by the cleaner shrimp Ancylomenes pedersoni: Do anemone host species, prior experience or the presence of conspecific shrimp matter? Journal of Experimental Marine Biology and Ecology. 2012 DOI: 10.1016/j.jembe.2011.11.026.
  5. Patterns of cleaning behaviour on coral reef fish by the anemone shrimp Ancylomenes pedersoni. Journal of the Marine Biological Association of the UK. 2012. DOI: 10.1017/S0025315411001822.
  6. Effects of three Caribbean cleaner shrimps on ectoparasitic monogeneans in a semi-natural environment. Coral Reefs. 2010. DOI: 10.1007/s00338-009-0583-8.
  7. Possible synonymy of the western Atlantic anemone shrimps Periclimenes pedersoni and P. anthophilus based on morphology. BULLETIN OF MARINE SCIENCE, 65(2): 407417, 1999.
  8. Lack of strategic service provisioning by Pederson’s cleaner shrimp (Ancylomenes pedersoni) highlights independent evolution of cleaning behaviors between ocean basins. Scientific Reports. (2019) 9:629 | DOI:10.1038/s41598-018-37418-5.
  9. Titus BM, Vondriska C, Daly M. 2017 Comparative behavioural observations demonstrate the ‘cleaner’ shrimp Periclimenes yucatanicus engages in true symbiotic cleaning interactions. R. Soc. open sci. 4: 170078. http://dx.doi.org/10.1098/rsos.170078

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