Dwarf Shrimp External Anatomy

Shrimp external anatomy

In this article, I am going to talk about the external anatomy of the shrimp. However, I would like to start off by saying that, there are so many types of shrimp that it is absolutely not possible to mention all the differences between them. Actually, anybody who will be able to do that will leave their names and legacies in the science. That is why I will describe the dwarf shrimp anatomy in general.

In short, shrimp external anatomy comprises a rostrum, carapace, abdomen segments, telson, pleopods, pereiopods (legs), maxilliped, and antennule. 

Quite often in my articles, I have to refer to different parts of the shrimp’s body. Although in most cases, I usually provide additional pictures for that, it is still not enough, in my opinion. Sometimes people need to see the full picture for better understanding.

Dwarf Shrimp Body Structure.

Dwarf shrimp belong to the class of invertebrates. They do not have bones (spine) or any internal skeleton. Their body is covered with an exoskeleton (shell), which is divided into two main parts:

  • The cephalothorax.

The cephalothorax is the result of the merger of the rostrum (“Beak-head”) and the carapace bearing all the appendages except the pleopods, and uropods. This part of the shrimp body protects their vital organs (brain, heart, stomach, bladder, testicular or ovarian).

  • The abdomen.

The abdomen of dwarf shrimp includes 6 abdominal segments, pleopods, and the tail (consists of telson, uropods, endopod, and exopod). It is the main muscle which allows shrimp to swim.

Shrimp external anatomy

 Quick Notes about Shrimp Body Structure

Scientific names Customary name Function

Cephalothorax consists of

Carapace Upper body Protection of inner organs
Antennae Whiskers


The sensor of orientation and coordination
Antennule The sensor of chemical information
Maxillipeds Jawfoot For eating
Pereiopods Legs Movement
Chela Claws (or Fans) Holding and picking food
Scaphocerit Fang Equilibrium and orientation for swimming
Eyes Eyes Vision
Rostrum Beak or Nose Protection of eyes, stabilizer

Abdomen consists of

6 Abdomen segments Stomach Swimming
Pleuron Protection of abdominal segments
Telson Tail Swimming
Pleopods Swimmerets Adaptation for swimming, holding and fanning eggs
Petasma Male organ Insemination


The carapace is heavily calcified upper part of the shrimp body, which protects the cephlathorax. It is thicker than the shell elsewhere on the shrimp. The carapace connects to main legs (pereiopods), maxillipeds, whiskers (antennae and antennule) and eyes of the shrimp.

I highly recommend to read my article “How to Supplement Shrimp and Snails with Calcium”.


Dwarf shrimp RostrumRostrum (from the Latin rōstrum meaning “Beak”) is a hard extension of the shrimp’s carapace that prolongs forward of the eyes. It does not have any sensors. However, rostrum has 2 important functions:

  1. The protection of the shrimp’s eyes.
  2. The stabilizer of the shrimp when it swims backwards.

Note: When it comes to taxonomy (the species identification of shrimp), the shape of the rostrum plays a very significant role.

Stalked Eyes

Dwarf shrimp EyesThe eyes of the shrimp sit either side of the rostrum. They are located on the short, independently movable and adjustable eyestalks. Shrimp have compound eyes, which give them panoramic vision. Their eyes are very good at detecting movement. Which is especially important for shrimp because they are at the bottom of the food chain.

Interesting fact:  The eye stems are also responsible for production of the hormones, which regulate metabolism, molting process, the location of the pigment in the cells, and the accumulation of calcium in the body.

Shrimp can regenerate their lost limbs with every molting process. However, unlike other body parts, shrimp cannot regenerate the eyes.

Antennae and Antennule

Dwarf shrimp Antennae and AntennuleAntennae and Antennule are paired, usually, flagellate appendages projecting from the front end of the cephalothorax. Dwarf shrimp have:

  • Two sets of short antennules (first antennae).
  • One set of long antennae (second antennae).

They use long antennae to gather tactile information from the environment. Antennae can easily catch water vibrations around the shrimp. Thus, it allows shrimp to feel where (what) they touch and helps them to orientate and coordinate their positioning.

The short ones also help assess the suitability of food and provide chemical information (“taste” and “smell”) about what they are touching.


Dwarf shrimp ScaphoceritScaphocerit is flattened plate, which is located at the base of antennae and antennule. It looks like a “Fang”, but it is not. Actually, this is an organ of equilibrium. Scaphocerit contains sensitive bristles that orient the shrimp in relation to the earth’s gravity.


Dwarf Shrimp Abdomen The dwarf shrimp abdomen is made up of 6 abdominal segments and contains most of the musculature. The first segment is just behind the carapace and the sixth segment is in front of the tail. The shell of the abdomen segments is significantly thinner than the carapace. Each segment has a separate overlapping shell, which can be transparent. Each abdominal section also has a pair of pleopods, except the last one (near the tail). Shrimp can swim backward by a rapid contraction of its abdominal muscles, powerfully flexing the abdomen.

Note: When shrimp molt, they have a breaking point at the junction of the first abdominal segment and the carapace.

Interesting fact: There are some species of shrimp in the ocean, which can hold the world record for darting speeds. By squeezing their abdominal muscle, they have been clocked at over 200 meters per second. It is close to the bullet’s speed!  


Dwarf shrimp UropodsThis is a paired, biramous appendage which is attached to the sixth abdominal segment. Uropods flank telson from both sides. Because of their shape, people also call it a “tail fan” which usually functions as locomotion when swimming backwards, and function like rudders, steering the shrimp when it swims forward.  


Dwarf shrimpTelsonThe 6th abdominal segment ends in the telson. It is not a real segment because it never has any pleopods. Shrimp actively use it when swimming.  



Pleopods (swimmerets)

Dwarf Shrimp PleopodsPleopods are shaped like paddles and are used for carrying eggs and swimming forward. In addition, in the male, the first pair of pleopods is modified for insemination (see Petasma). There are 5 pairs of pleopods (swimmerets) on the underside of the abdomen. They are tucked under the abdomen of the shrimp.  Each abdominal segments has one pair of pleopods.  

Pleuron (Pleura)

Dwarf Shrimp AbdomenPleuron is one of the lateral flaps on each of the anterior five abdominal segments. Basically, it is what overlaps the nearby abdominal segments. The main purpose is the protection of the junction between different abdominal segments.

Petasma (Petasmata or Appendix masculina)

Dwarf shrimp Appendix masculinaThis is the male genital organ (Appendix masculina). It consists of the much enlarged and coupled endopods of the first pair of pleopods. The shape of a petasma is the easiest way of distinguishing between Neocaridia and Caridina shrimp.

You can read more about “The Difference between Neocaridina and Caridina Shrimp” right here. 

Pereiopods (Legs) and Chela

Dwarf shrimp Pereiopods and ChelaDwarf shrimp have 5 pairs of jointed legs. However, they have a different function:

  • the first 2 pairs of pereiopods have tiny claws / pincers / fans (Chela). Shrimp use them for feeding and fighting between themselves for food. However, because the claws are too small, they usually cannot harm each over.
  • the next 3 pairs of pereiopods are used for walking as well as for “sensing” the environment.  


Dwarf shrimp MaxillipedMaxilliped (jawfoot, and foot jaw Origin: [Maxilla + L. pes, pedis, foot.]) is one of a pair of 3 sets of the mouth appendages on the heads of the shrimp modified to rummage and bring food to the mouth.

Note: Actually only two pairs of maxillipeds take part in the feeding process. The third pair (the longest) is usually used as a “semy-leg”. Maxillipeds are almost in constant movement as shrimp find and manipulate tiny morsels of food to its mouth.

Related articles:

Crayfish Internal Anatomy
Crayfish External Anatomy
Crab External Anatomy
Crab Internal Anatomy

11 thoughts on “Dwarf Shrimp External Anatomy

  1. Very good read, i really like this and learn a lot!
    Thanks for it!

  2. Do you have an article for abnormal anatomy like the darkening over the gills? If you do have that do you go into detail of the possible causes? Thanks!

    1. Hi Leah Weisel,
      Do you have a picture?
      What are your water parameters? Ammonia?
      Best regards,

    2. Copper overdose? get a copper test kit and see if there’s excessive copper in your tank.

  3. Do you have any information on genes/genetics on any species of dwarf shrimp.
    If not, do you know of any procedures that have been done on the chromosomes.
    Thanks in advance
    Dick Grossberg

    1. Hi Dick Grossberg,
      I love shrimp keeping and read a lot of scientific literature but this goes beyond my knowledge.
      Best regards,

  4. This was quite an interesting read, thank you for posting this.
    I only came across it to answer a simple question of ‘do Shrimp have ears?’
    I have learnt they do not 😂

    1. Hi Wendy,
      You’re very welcome! 🙂
      It’s fascinating how some questions can lead to discovering more))
      Best regards,

  5. Great, great explanation. Where can I find the same for prawns, please?

    1. Hi Basma Lamb,
      Maybe in the future I will write one.
      Best regards,

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