A Few Common Shrimps for the Marine Aquarium

By James W. Fatherree, M.Sc.

If you own a marine aquarium, or are thinking about getting one, you've probably already noticed that shrimps are good for more than just eating.  All sorts of them can make great additions to reef and non-reef aquariums alike, often being very colorful and/or interesting.  So, I want to give you some information about them. First a little basic stuff about shrimps in general, and then a little more about a few of the common varieties you’re likely to come across at the shop.

To start, shrimps are a type of arthropod, and all arthropods have a few things in common.  For example, they all have an even number of jointed legs, which is where the name of the group is derived from.  "Arthro" means joint and "pod" means foot or leg.  They also have segmented bodies and well-developed organ systems, including a circulatory system with a heart, and a nervous system with a brain.  Well-developed sensory organs, such as antennae and/or compound eyes (like a fly’s eyes) are also the norm for arthropods.  And, they all have a durable shell or tough skin, which is called an exoskeleton ("exo" means it’s on the outside) or cuticle.  So, with all that said, you should be able to see that lobsters, crabs, insects, and spiders are all arthropods and cousins of the shrimps.

Of these, the shrimps, lobsters, and crabs have their own place within the bunch and are placed into a group called the decapods, which means "ten legs" ("deca" means 10).  This is because they all have 5 pairs of appendages that have been modified into legs.  Many have their first pair of these legs modified with enlarged pincers/claws, as well.

As far as outward appearances go, shrimps come in a variety of shapes, sizes, and colors.  They also exhibit as many different lifestyles and behaviors, and have diets that are highly variable as well.  But, in the aquarium they tend to be just as adaptable (if not more) as many fishes prove to be, and quickly learn to eat just about any kind of fish foods.  Flake food is a favorite, but brine shrimp, dried shrimp pellets, blood worms, or any sort of meat will usually be taken, as well.  It’s amazing to me how an animal, whether it be a fish, a shrimp, or even a starfish can tell that flake food is indeed food the second it hits the water (even the first time), but they can.  It must smell awfully good to them!

As you'll see in a minute, there are also several kinds of shrimps that make a living by picking off and eating parasites, dead skin, and other materials found on "dirty" fishes.  These "cleaner shrimps" have some sort of coloration and/or behavior that lets fishes know that they can get a free cleaning if they’ll be nice enough not to make a meal of the cleaner.  So, cooperative fishes will come to a shrimp and sit still, or move around slowly, and will let the shrimp go over their body and pick them clean.  Sometimes big fishes will even open up and let a cleaner shrimp crawl inside their mouths and pick their teeth and gills clean as well.  Obviously, this is a very beneficial service as it is hard to imagine a fish passing up such an easy meal without a good reason.

Do keep in mind that even cleaner shrimps won't last around some fishes.  Occasionally, Triggers may gobble them up, Hawkfishes may tear them apart, and Lionfishes might slurp them down, as will other ill-mannered, uncooperative tankmates.  The odd thing is that in other cases, the same sorts of fishes may get along with the shrimps just fine...

Unfortunately, sometimes these same shrimps don’t seem to want to do their job in an aquarium, though.  I don’t know why, but many times cleaner shrimps just won’t clean.  It doesn’t seem to have anything to do with the fishes in the aquarium either.  It just happens.  In addition, I also have to warn you that on occasion, a larger predatory fish may just get a little too hungry or excited.  I've seen a lionfish slurp up a rather expensive new cleaner shrimp before it even made it to the bottom of the tank!  I’ve never tried keeping any sort of shrimp with an aggressive triggerfish, but I know they can be just as dangerous.  I've also read of at least one occasion when a cleaner was eaten by a Hawkfish, and another was eaten by a large wrasse.  Of course, as far as all of the non-cleaner shrimps go, they are essentially tasty snacks for just about anything that eats meat and can catch them, so always pay attention and don't make a mismatch.

Lastly, it is important to point out that many shrimps can be particularly sensitive to rapid changes in water parameters/quality.  Thus, you'll need to make sure to be patient and take your time when acclimating a shrimp to its new home and treat it just like a new fish.  Add a little water to the bag, wait, add, wait, add, wait, add, wait, then release.  Or, even better, use a length of airline tubing with a knot in it to siphon water from the tank to the container the shrimp is in.  The knot can be adjusted to slow the flow down to a slow drip. Depending on the species and aquarium conditions, if they make it through acclimation, and you don’t have anything in your aquarium that is going to eat them, shrimps have the potential to live a surprising number of years.  The record to date, as far as anything I've had myself, goes to a seven-year old banded coral shrimp. That's a long time, and it’s still alive!

Now with the general stuff covered, I’ll get on with some of the more common shrimps found in marine aquariums.  As I have witnessed, like many other creatures, each individual of each species can have it’s own personality to some degree, so it can be difficult to tell you exactly how every shrimp of every species will act all the time.  Instead, I’ve provided what I can to give you a general idea of what to expect.

This has got to be the all-time, number-one, favorite shrimp, Lysmata amboinensis, the Skunk Cleaner.

The Skunk Cleaner Shrimp: Lysmata amboinensis

I'd have to guess that the Skunk Cleaner Shrimp is definitely the most popular of the popular shrimps. They've been around forever and you can find them in just about any shop.  I'm guessing the stripe down the back is the origin of the skunk part of the name, and the rest of the name makes it pretty obvious that these are cleaners.  In fact, they are the best cleaners, and unlike some of the others, they will actually work on fishes just about any time they get the chance.  There are exceptions, of course (there always are), but they are so happy to do what they do that on many occasions I've seen them climb on a relatively big fish and go for a ride.  They hang on and work while the fish goes about its business. If you really want a shrimp that will help earn its keep, this is the one to get.

Keeping more than one in an aquarium isn't a problem either, as they don't mind each other at all.  Sometimes smaller fishes seem to be a bit a wary about getting cleaned by a shrimp that is as big as (or bigger) than they are.  But, if you happen to have a few bigger fishes, like some angels or tangs, adding a couple of skunk cleaners can be really fun to watch because on occasion, they'll double-team bigger fish and really give them a good going over.

I'm still not done.  Another thing that I really like about this shrimp is its ability to swim around at high speed right side up or upside down.  If you drop some flake food in, you can sit back and watch skunk cleaners zoom to the top, then flip upside down and run around in circles grabbing every flake they can get grab. Round and round they go... Lastly, I need to point out that I’ve never seen or heard of one of these shrimp bothering any other sort of invertebrates.  They seem to be perfectly safe with anything you can put in a tank.

The Blood Shrimp, Lysmata debelius, has a very appropriate name.  The deep red color is quite nice.

The Blood Shrimp: Lysmata debelius

This shrimp is well-known for its deep red color, so the name "Blood Shrimp" is quite appropriate.  The white antennae and a few spots here and there make them look even better.  I have also heard them called "Scarlet Cleaner Shrimp," which confirms that they are indeed, cleaners. However, in my experience, many of these have not been quite as eager as the Skunk Cleaners when it comes to doing their job.  In addition, these are more likely to hang around in rockwork caves and crevices in the tank and can even be a bit shy at times, unlike the Skunks that stay out in the open almost all the time.  But, I still like them a lot anyway.

In their natural settings, Blood Shrimp are often found in living male/female pairs.  But, I haven't had any problems keeping just one in an aquarium.  I doubt if it's possible for a shrimp to feel lonely (I hope not). Conversely, if you want two or more, you shouldn't have any trouble, either.  They get along fine in groups of any numbers.  These have a clean history, as well, when it comes to leaving other invertebrates alone. I haven't seen them bother anything.

This is the Banded Coral Shrimp, Stenopus hispidus.  Don't try more than one unless they are mates, or you have a really big tank.

The Banded Coral Shrimp: Stenopus hispidus

Also commonly called Coral Banded Shrimp, these are bigger cleaners that are aptly named for the red, white, and black bands that cover their bodies.  However, I have to say that I personally have never even once witnessed one cleaning a fish in an aquarium, and have only read about this and seen it in underwater photos. They can get considerably larger than the other cleaners, too, and I think they might eat a small enough fish rather than clean it if given the chance.  To make matters worse, despite their beautiful looks, the vast majority tend to hang out in/under/behind rockwork leaving only their long white antennae out for viewing. They hide a lot.  But, there are occasional individuals that stay out much more than others, and almost any will make an appearance at meal time.

Banded Coral Shrimp can also be found in mated pairs, and occasionally you may find such a pair for sale together.  In this case, the two were collected together and shipped together, etc. and will stay together peacefully in your aquarium.  However, it is practically impossible to buy two of these shrimp separately and get them to pair up in a tank.  They don’t like each other at all, and certainly can’t be kept in groups.  The bigger one(s) will kill the smaller one(s) until there is only one left, unless you have a really large tank that allows them to avoid each other.  They often won't get along with other types of shrimps either, but they typically don’t bother other invertebrates.  So, if you want one (or a pair), it will be fine in a reef tank.  The only thing to watch out for is a hungry shrimp that might climb up on a coral and steal its food. Make sure the shrimp eats before giving meaty foods to corals.

The Peppermint Shrimp, Lysmata wurdemanni, isn't the greatest cleaner, but at least they'll keep unwanted Aiptasia anemones in check.

The Peppermint Shrimp: Lysmata wurdemanni

Peppermint Shrimp are cleaners, too, although again the common name doesn't tell you this.  But, in aquariums they are also less likely to come out and interact with fishes than Skunk Cleaners or Blood Shrimp (but much more likely to than Banded Coral Shrimp). They are also rather plain in appearance relative to the other shrimps, being named for the thin red stripes on their bodies.  It's this lack of color, particularly the lack of white antennae, that makes me think that fishes might not readily recognize that they are cleaners, hence their typically poor performance.  Notice that the rest of the cleaners have them, except Peppermint Shrimp. Just my guess and no actual data to show...

Anyway, they are still interesting critters nonetheless, that do have some positive qualities.  Many, many times they have come to the rescue in aquariums when Rock Anemones (Aiptasia spp.) have sprung up.  These nearly indestructible little buggers are well known for burning and even killing corals, but for reasons unknown they happen to be on the Peppermint Shrimp’s menu.  <Editor's note: This species has been implicated in nipping clams, corals, and other cnidarians, so do consider this when adding one to your reef tank> In addition, any number of them will get along with each other, and if kept in pairs or groups they can reproduce rapidly.  I've seen some other shrimps reproduce in aquariums, but I don’t know of any that make babies like these guys.

This is the Camel Shrimp, Rhynchocinetes durbanensis, sitting on a Tridacnid clam. While its occasional climbing around was irritating to the clam, this shrimp never did any sort of damage.

The Camel Shrimp: Rhynchocinetes durbanensis

So, now we've gotten to a non-cleaner. They look cool anyway, being named for the high arch of their back, but they won't last long at all if there are fishes around that like to eat little meaty creatures.  A "non-cleaner" shrimp

is a non-cleaner, meaning that it is nothing more than a tasty meal for many bigger fishes. And, unlike the other shrimps I've covered, these can be a danger in a reef aquarium, as they are well-known for their bad habit of occasionally snacking on various soft coral polyps and mushroom anemones.  So, be wary of where you try to keep one of these.  They're still interesting little creatures though, and they can be kept in groups in an appropriate aquarium, if you still want to try them.

 

 

Ok, Ok, Ok! Just a few words about some that aren't so common...

Here's a shot of the psychedelic-looking Harlequin Shrimp, Hymenocera picta.

The Harlequin Shrimp: Hymenocera picta

The Harlequin Shrimp is without a doubt the oddest looking shrimp you'll come across.  It's difficult to even peg it as a shrimp at all due to its flamboyant appearance. It's a real shame, though, as they are also the most difficult shrimp to maintain.

Unfortunately, they only eat starfishes and a few of their relatives!  While all the other types of shrimps will eat fish foods, these will want to eat sea stars, serpent stars, and brittle stars.  So, if you want to keep one (or a pair) be ready to provide some costly meals.  If you aren't interested in taking care of their needs, leave them at the store.

Anemone Shrimps

Anemone Shrimps, like Periclemenes and Thor, are relatively small shrimps that live in symbiotic relationships with stinging anemones.  They spend all their time hanging out between an anemone's tentacles, but like a clownfish, they don't get stung or eaten.  This of course, makes it very difficult for something else to eat them. They’ll do fine if you provide some fish foods, but they should be kept with an anemone, so I wouldn't try one in a fish-only aquarium. <Editor's note: Since Periclemenes species do require the presence of an anemone, and have not proven to be particularly long-lived in  captivity, you should keep them only if you're up to the challenge of providing them the proper care.>

Pistol Shrimps

Pistol shrimps, like Alpheus, are almost never seen for sale, but they often end up in tanks anyway.  They are sometimes hitchhikers in live rock or live sand, and you'll know that you got one if you hear loud pops coming from your aquarium at night. These pops, which are where the name comes from, are produced by specially modified pincers, and are used to warn off or stun other creatures.  How loud? Loud enough to be heard at the other end of the house.

Just maybe, you'll come across a Pistol Shrimp that lives with a goby.  Gobies don’t dig as well as the shrimp, but apparently they can see much better.  So, some have developed relationships in which the shrimp digs and maintains a burrow for both of them, while the goby watches for any signs of danger.  Of course, you'll need a tank with a deep substrate if you have the desire to take them home with you.

Saron Shrimps

Aggressive, carnivorous, and fairly large.  How much more do I need to say?  Saron Shrimps (Saron spp.) can get considerably bigger than the rest of the shrimps discussed here, and can be downright nasty to anything small enough to be victimized.  They'll eat several types of corals and such, and may also kill Tridacnid clams. And, to top it off, they are nocturnal, so you won't see them much.  Still, in a larger aquarium with fishes and other critters that can handle themselves, they are a potentially interesting choice of livestock if you are looking for something a little different.

Mantis Shrimps are extremely cool, but they aren't really shrimps. They're Stomatopods. Maybe we'll come back to them sometime in the future.

Mantis Shrimps

Sorry to disappoint, but they're not really shrimps at all, despite the common name.  Maybe we'll get to them another time...

That's it! There are many others, of course, but these are the ones you'll be very likely to see in stores, and a few that you may see from time to time.  As I preach all the time, do your homework on anything you may be interested in purchasing before you buy, not after.  I've given you enough information about the most common shrimps to get you on your way, but anything else will need to be researched further.

References

Calfo, A. and R. Fenner. 2003. The Natural Marine Aquarium Series: Reef Invertebrates, An Essential Guide to Selection, Care, and Compatibility. Reading Trees, Monroeville, PA. 398 pp.

Rupert, E. E. and R. D. Barnes. 1994. Invertebrate Zoology, 6th ed. Saunders College Publishing, Fort Worth, TX. 1140 pp.