Showing posts with label Invertebrates. Show all posts
Showing posts with label Invertebrates. Show all posts


ANEMONES - What You Should Know

Plate V in "British Sea-Anemone and Coral...
Plate V in "British Sea-Anemone and Corals" by Philip Henry Gosse, Van voorst, Paternoster Row, London, 1860. 
(Photo credit: Wikipedia)

Have you ever been to a pet store and as you looked at the fish tanks you noticed something kind of weird? You began to observe it and after a while, it looked kind of neat. You read the label and you see that this weird, neat thing is called an anemone. Your mind immediately begins to race as you think of how cool it would look in your tank. Well, the truth is that it would look cool.

However, you should understand a couple of things about the anemone first. So let's take a brief look at a few common facts you should know. First, let's look at how to pick out the right anemone. Try to figure out something about your desired anemone ahead of time. This will make it much easier to tell if something is wrong. If you see an anemone with short tentacles that should have long ones then that might mean this particular one is not healthy.

Also look for spots on it that may be torn, especially near the bottom. If this is torn then it may not be able to attach to anything. Proper color should also be something to look for in judging its health. Now that you know a few tips for picking out your anemone let's look at some guidelines for keeping your anemone. For one, there should be no possible way for it to get sucked into the filtration on your tank. A good way to prevent this is to cut the end off of some tights and place it over the filtration. Also, good water quality is a must. Anemones can be sensitive to the water in which it is placed and therefore water quality must be good at all times.

Lighting should be of high quality as well. Anemones thrive with a high light source and metal halides are recommended. Feeding can be different for every particular anemone. Test it out to see how yours does with different techniques. Usually feeding a couple times a week using frozen brine shrimp is adequate and the use of various minerals will also help. If the anemone continues to look healthy this is a sign that it is being fed properly. If it is not then try feeding more often with various types of food. Last, let's look at keeping an anemone with coral. This can be a little tricky because some anemones like to travel around the tank at times.

This may not be good, because this means it has not found a good place in which it is comfortable. If this is the case then you might want to consider waiting until it has found its "comfort zone" before adding any coral. When placing coral with an anemone make sure there is plenty of room between it and the coral. If they touch one another it could cause death for both since many corals sting as well as anemones. Plan things out before you consider keeping both.

So now you know a couple of things relating to the anemone. Once you get the hang of keeping one, it is safe to say that there is nothing really quite like it. To see an anemone flowing to the current in your tank and the possible clownish or two making it their host is simply amazing. Good luck on this marvelous journey and I hope you have great success with your new anemone!


CLOWNFISH and SEA ANEMONE: Symbiotic Relationship

LARGER On Black Ocellaris clownfish, Amphiprio...
On Black Ocellaris clownfish, Amphiprion ocellaris. Some clown anemonefishes are brave.
When divers close to them, papa anemonefish will swim out to defense. (Looks like very angry!!) But, often they will hide. (papa will hide faster than their babies. haha~) Lovely!!
(Photo credit: 
Clownfish or the anemonefish are small fishes belonging to superclass Pisces and family Pomacentridae. There are about twenty-nine species of clownfish are known all over the world out of which one belongs to the genus Premnas and others are kept in the genus Amphiprion. As their name indicates they form symbiotic mutualistic associations with the sea anemones in the ocean world. 

Depending upon the species these may be overall yellow, orange, reddish, or blackish while others may bear patches or bars. The largest species are not to attain a body length of about 18 centimeters while the normal range of body length is about 10 centimeters. The well known popular movie entitled Finding Nemo by the Pixar/Disney figures out the clownfish as the leading character.

Clownfish are known to inhabit the warmer waters of Indian and Pacific oceans along with the Great Barrier Reef and the Red Sea. The majority of the species are known to dwell in restricted areas while others have a wide range of distribution. They are generally hosting specific but some species also show coordination with other species also. They are known to dwell at the bottom of the seafloor confined in the shelters of lagoons or coral reefs. They prefer to live in pairs. 

They are also distributed in northwest Australia, Southeast Asia, Japan and the Indo-Malaysian region but totally absent in the Caribbean region. They are known to feed on small invertebrates otherwise they may cause damage to the sea anemone. The fecal matter released by these fishes acts as a source of nutrients for the sea anemone. They are strictly omnivorous and their gut content has revealed that their diet includes 20-25% of algae. The diet comprises of copepods, algae, zooplankton, and algae. They also feed on small crustaceans and mollusks. When kept under captivity they are provided fish pellets and fish flakes and food. They also feed on the undigested food material of the sea anemones.

Clownfish and certain damselfish are the only known species of fishes which are able to remain unaffected by the poison secreted by the sea anemone. Many theories have been put forward to support this view. According to one view, the mucus coating of the fish may be composed of sugars rather than proteins so the sea anemone fails to recognize the fish as food sources and does not attacks it. Another view suggests that due to co-evolution clownfish have developed immunity against the toxins secreted by the sea anemone. 

It is well known that they tend to live in pairs in a single anemone and when the female dies the male changes its sex to female. This process is known as sequential hermaphroditism. Clownfish are born as males and that is why they are protandrous hermaphrodites. On top of the hierarchy reproducing females is presently followed by the male but if the female dies this hierarchy gets disrupted. The largest member of a group is a female and the second largest one the male. Clownfish are neuter which means that they do not have fully developed sex organs for either gender.

Clownfish prefer to lay their eggs on flat surfaces where they can adhere properly. Spawning generally occurs around the time of the full moon. The male is known to guard the eggs until they hatch after 8-10 days. They lay eggs ranging from hundreds to thousands. They are the first known fishes to breed in captivity. The average life span is of 6-10 years but in captivity, they live up to 3-5 years. They show a special association with the sea anemone. The activity of these fishes results in a greater amount of water circulation around the sea anemone and sea anemone provides them protection from its toxins. Clownfish depends on the sea anemone for its daily food. 

When anemone paralyzes a fish and consumes it these fish eat the chunks and pieces left after the feeding of the anemone. The fish also keeps the anemone free by eating up its dead tentacles and act as a lure by attracting predators towards itself by its bright coloration. This sort of symbiotic association of the clownfish with the sea anemone makes them the most astonishing creatures living underwater. They are known bred in captivity in the marine ornamental farms in the USA. If the anemone of the aquarium dies they tend to live in the soft varieties of corals. The corals may agitate the skin of these fishes and in some cases may kill the corals also. Once they get confined in the corals they defend it. We can conclude that they are amazing fishes showing unique features.



Aiptasia sp.
Aiptasia sp. (Photo credit: Wikipedia)
Aiptasia in residential aquariums will quickly be wiped out due to the wide adoption of Bergia Nudibranches now available in Canada. The key benefit of this amazing animal is that it only feeds on Aiptasia, accordingly making it a safe addition for the rest of the tank.

Aiptasia has been a sore-spot for home aquarists for decades. Thankfully, the Berghia is very small in size and can get into those tiny spaces, without harming coral or liverock. Nudibranchs are the only species able to consume the entire aiptasia, and therefore prevent aiptasia regrowth and spawning. Another benefit is that the Berghia are so small, they won't add bioload to the tank, or affect the quality of the water.

Berghia are quick reproducers too, due to their hermaphroditic nature. Mature adults can lay eggs every day. On a side note, you have to be aware that the Berghia feeds solely on Aiptasia, and for that reason must be monitored, as once the eradication of the Aiptasia happens, the creature will starve to death.

Berghia are very smart little creatures. They have sensory organs known as rhinophores thata are able to use chemicals to find the location of the Aiptasia. This means that Berghia can find even the tiniest Aiptasia, not visible to the naked eye, and wipe out the parasite completely before it reaches adulthood. Berghia are able to eat the Aiptasia successfully, because of strategies it employs to approach the Aiptasia without the parasite feeling endangered. This prevents the release of the tentacles and larva, meaning it prevents new reproduction from occurring. Berghia is also harmless to the other fauna and flora in the aquarium and primarily feed at night, which won't affect the beauty of your tank during the day.

Berghia coerulescens eats Aiptasia couchii - Photo: Wikipedia

What to Expect after the Introduction of Berghia
The recommendation is for every 100 gallons of water that 8 Berghia be introduced to the tank, for a moderate to severe infestation of Aiptasia. If there are only a few Aiptasia anemones present, it is not recommended to add Berghia to the tank, as it won't have enough food to sustain itself, and will starve to death. Berghia are a species of sea slug and need the appropriate environment to thrive and survive in. Keeping this in mind, there are some areas where this sea slug won't be able to help, such as if an infestation occurs in the tubing, powerheads, or the sump. These areas should be kept clean at all times by you, the reef owner to prevent the spread of Aiptasia.

How long will it take for Berghia to wipe out the Aiptasia infestation?
This primarily depends on how bad the infestation of Aiptasia is, and how many Berghia have been introduced into the tank. It should be assumed that for 8 Berghia, two to three months would be an appropriate amount of time. It's so important to not get discouraged if you don't see immediate results. Berghia need time to acclimate to their new surroundings before they are able to wipe out the infestation.

Caring for Berghia
There are many species of animals that are considered quite safe for reef aquariums, however, this is not always the case. Here are some species to avoid in an aquarium containing Berghia. Avoid any nocturnal species that hunt near the liverock, or coral, such as butterflyfish, filefish, wrasses, and some species of dotty backs. Other species which prey on Berghia include peppermint shrimp, coral-banded shrimp, and some invertebrates, such as the arrow crab, sally lightfoot crab, pom pom crabs, and emerald crabs. Aiptasia can consume Berghia if the sea slug is placed directly into its mouth. Therefore, take precaution when adding the Berghia into your reef tank.

In conclusion, nature has answered the Aiptasia infestation with a natural predator, the Berghia. As long as it acclimates to its new surroundings, it will eradicate the Aiptasia infestation, and keep the population under control. It is so important to keep the tank well cared for, to ensure the health of the creatures that inhabit the reef. With attention and care, the saltwater aquarium can be danger free of unwanted parasites, and be a beautiful addition to any home.


Importance of Saltwater INVERTEBRATES to the REEF AQUARIUM

Riffbecken (Photo credit: Wikipedia)
Simply put; No reef tank is complete without invertebrates. Invertebrates provide numerous benefits to the marine aquarium, the same way they do in nature. Algae and fish waste removal are two of the main benefits, however, there are countless others. In this article, we will discuss some specific groups of inverts and how they can help you keep your reef healthy.

The first group of inverts we will discuss are algae eaters. Algae eaters can help keep an aquarium looking clean and presentable during cycling, algae blooms and normal growth in an established aquarium. Nuisance algae such as cyanobacteria (red slime), brown diatoms, bubble algae, green algae and hair algae can all be battled with diet specific inverts. Select species of crabs, hermits, snails, sea slugs, sea urchins, and starfish can provide excellent algae control, as well as add color and diversity to the tank.

Another group of inverts to address are the detritus eaters. Detritus can be described as an organic matter that naturally occurs in the aquarium; some examples are leftover fish food and fish waste. Detritus can build up in the tank, dissolve in the water column and cause elevated levels of ammonia, which is the number one fish killer in home aquariums. To avoid this build-up of detritus, we can put invertebrates to work doing what they naturally do in the wild. Select species of crabs, hermits, shrimp, sea urchins, starfish, anemones and sea cucumbers can help keep detritus under control, therefore keeping water parameters in check and your fish healthy.

We have only begun to discuss the need for invertebrates in the reef aquarium. There are many interesting species to learn about, and many beautiful critters that can safely be kept with your fish and corals. A good mix of invertebrates can help you achieve a thriving, healthy aquarium with a 24-hour-a-day maintenance crew!



Berghia Nudibranch


How To Keep INVERTEBRATES In Your Marine Aquarium

English: This photograph of a Sea Apple at Can...
This photograph of a Sea Apple at Cannibal Rock in Indonesia (Photo credit: Wikipedia)
Keeping Invertebrates And The Care They Need
Invertebrates are not as hardy as fish. It is necessary to make a study of Invertebrates and how they function, their diet and the temperature that they need before attempting to acquire them. You will need to make arrangements with your supplier because you may need delivery of food if so required. There are two types - coldwater and tropical. It should also be noted that they need to merge with the others in the tank.

The Different Types Of Invertebrates
As you make a study of the Invertebrates, you will find that there are two types - coldwater and tropical. A few examples are sea apple, red hermit crab, and shrimp. The water temperature should be 75 and 79 degrees F, and the PH between 8.2 and 8.4 and the salt water content between 1.020 and 1.024. This needs to be checked every day so that there is no discrepancy. Also, their food is not compatible, so your supplier needs to be informed.

Coldwater Invertebrates can only be fetched from tide pools as the stores do not keep them. One thing that is required is to see that these do not belong to an endangered species when removing them from their habitat. A comprehensive research needs to be done so that they can be taken care of appropriately and all their dietary needs are met. They usually feed on shrimp, mussels and raw fish.

Another useful tip while keeping coldwater Invertebrates is to always keep scallops and mussels in a tank so that you will always have a regular supply for them, and it may be a good idea to give them fresh rather than frozen food. They should also be fed a little at a time at regular intervals.

When a tank is set up, live rock is a good idea, because some Invertebrates like to take their food from the parasites that are found on the live rock. There are innumerable ways in which you could fill your aquarium so that your fish are comfortable in their surroundings and it is a pleasure to look at. If you have a substrate, shrimp and crabs can make deep pits and go underground. That would be as close to their natural surroundings as possible. If you would like to keep anemones, then a light could be installed, as they like the light. The main thing is to research your project, see what you get regular supplies, keep the tank clean and check for temperature, and you are all set to enjoy your aquarium. You will find that your time and effort has been well spent and you can enjoy your handiwork.

    Abhishek is an avid Fish Lover and he has got some great Aquarium Care Secrets up his sleeves!
    Article Source: EzineArticles



Sea anemones are a very common offering in the marine aquarium trade. All types of species are brought in from carpet anemones, filter feeding tube anemones to rose bulb tip anemones.

English: Sea Anemones at California tideppols....
Sea Anemones at California tideppols.
Sea Anemones look as plants,
but they are animals and they are predators.
(Photo credit: 

While most people think they are corals, sea anemones are actually under the phylum Cnidaria, which strangely enough, includes the jellyfish. They do share a common trait with corals, however. Within their bodies are contained symbiotic algae called zooxanthellae which extract energy from light and feeds the sea anemone with their by-products.

Where they differ spectacularly from corals are their ability to move from location to location. This behavior is commonly seen in captivity where the sea anemone will move around the aquarium until it has found a suitable spot.

Unfortunately, this behavior is undesirable mainly because their tentacles contain stinging cells used to capture prey and as a defense mechanism. As they move around the aquarium, they may come into contact with and sting any corals that are present.

The sea anemone shares a symbiotic relationship with a number of creatures in the wild. The most famous of their hosts are the clown fish family. They also play host to damselfish, certain crabs and a variety of anemone shrimp that rely on it for protection from predators.

They are a tricky species to care for in a marine aquarium as they require strong water flow and very strong lighting to do well in the long run. Should they die, they literally begin to melt. Which can really foul up the water?

Unfortunately, the great number of these creatures end up dying in captivity due to improper conditions. This is a shame because in the wild they are known to reach a lifespan of a hundred years or more. Some experts have pointed out that they may not even die if conditions remain good.

The family of Sea Anemone also contains a number of pests. Among them, the infamous Aiptasia and Majano anemones. Unlike their prettier cousins, these pests thrive in captivity and can quickly take over the entire aquarium.


Marine Aquarium Care - INVERTEBRATES Only

The care required for an invertebrate only tank is very similar to that of any other saltwater tank; however, the invertebrates are far less hardy than fish. It is recommended that you become skilled with a fish only tank before attempting an Invertebrate aquarium. Most Invertebrates require a specialized diet. Check with the supplier before purchasing and be sure that you are willing to make the commitment to have food delivered if necessary. There are two different types of invertebrates, tropical and cold water. Make sure that the type you are buying is compatible with its other tank mates.

DSC00294, Monterey Bay Aquarium, California
Reef Aquarium - Photo by jimg944 
A few examples of tropical invertebrates are tube worms, red hermit crabs, cleaner shrimp and the sea apple. All of this marine life is compatible in terms of water conditions. They require a water temperature between seventy-five and seventy-nine degrees Fahrenheit, a P.H. between 8.2 and 8.4 and a salinity content of 1.020-1.024. As you can see, there is very little wiggle room associated with these measurements. It is extremely important to check the levels daily, or the results could be costly. These invertebrates are not compatible, however, with their food source needs. Check with the supplier for compatibility before combining tropical invertebrates.

Unlike their tropical counter parts, cold water invertebrates are usually not sold in stores. They have to be collected from tide pools. It is important to make sure that these species are not on the endangered species list before removing them from their home. It is equally important to do research in order to verify that you are able to properly feed them and care for their very specific needs. Sea Anemones, prawns, shrimp, and starfishes are a few varieties that have been successfully maintained in an aquarium. They require a water temperature between fifty-four and fifty-nine degrees Fahrenheit, a P.H. between 8-8.4 and a salinity content of 1.024-1.025. Luckily they do eat the same food. They feed off of a diet of small pieces of raw fish, shrimp, squid, and mussels.

When keeping cold water invertebrates such as the species mention above, it is a good idea to keep a separate tank full of shrimp, mussels, and scallops to be used as a food source if you wish to use fresh rather than frozen foods.  Be careful when keeping shrimp, as all of the invertebrates listed above feed on shrimp, including shrimp themselves. It is unlikely, however, that a healthy live shrimp will be eaten whole by another shrimp or starfish. Invertebrates should be fed more frequently in smaller amounts than fish. Try to feed only an amount that can be consumed in the first thirty to sixty seconds.

When setting up an invertebrate tank remember to include live rock, because some invertebrates feed on the parasites that grow on the live rock. A substrate should also be included in this type of aquarium. It will provide a place for the crabs and shrimp to dig and bury themselves. A light should be included as well if you intend to keep anemones.


Saltwater Aquarium Stories - My CARPET ANEMONE

Saying Goodbye to my Carpet Anemone!

I purchased the carpet anemone secondhand with my aquarium and it came with 3 clown fish that were hosting in it, it quickly became the prize of my saltwater aquarium. In the first month I found that the anemone would move around the aquarium until it found a comfortable position. This proved to be a nuisance as it would knock over various corals and in some cases sting some of my corals. I found myself repositioning corals on a weekly basis. I decided to not to add any new live stock until the anemone appeared to remain in the one location.

English: Clown fish taking safety in a Sea Ane...
Clown fish taking safety in a Sea Anenome.
(Photo credit: 
Over the first 6 months I noticed the carpet anemone growing further in size and although this looked amazing, it was quickly becoming a problem. Carpet anemones have a powerful sting (as I experienced first hand) and they are also very sticky. I am certain I lost a blue tang because it accidentally swam into the anemone. Most other variety of anemones such as the regular bubble tip to do not have the same level of stickiness as a carpet anemone which means fish can accidentally get stung however can quickly escape, unlike with the carpet anemone.

I made an executive decision to remove the anemone from my saltwater aquarium. This was difficult as it was the home for 3 clown fish and having this relationship between fish and anemone is never guaranteed. Nonetheless I wanted a coral rich saltwater aquarium which I just couldn't have with the carpet anemone. I would suggest that if you are thinking of keeping a carpet anemone that you base your saltwater aquarium around the anemone, this will provide a less stressful experience. They are truly remarkable creatures. In terms of feeding your carpet anemone, they eat almost anything you feed your fish. I would use a turkey baster to feed my fish brine shrimp and I would just squirt some towards the mouth of the anemone. Otherwise I know of people who have cut up some cooked prawns and used that. Just remember if you have clown fish that host in the carpet anemone, they actually provide food and you will find the anemone to be relatively self sufficient.

If you had the same problem as me and needed to remove the carpet anemone from your saltwater aquarium there are various methods. If it is stuck to the glass on the side or bottom of your aquarium, you are in luck. Put a non toxic plastic glove on and grab a credit card. Use the credit card to slide behind the base of the anemone's stem to remove it from the surface. If it is attached to a rock, you can try removing using the same method, however I found it much easier to just sacrifice the rock and try and replace it with another piece of live rock. My local fish store gave me $200 credit for the anemone above however if I wasn't as desperate to remove it from my saltwater aquarium as quickly as possible, I could have sold it privately with the clown fish for probably $500. I kept the clown fish and after a couple of weeks their stress levels decreased and they made a new home within the several caves and tunnels in my saltwater aquarium.

Later on I will discuss what happened with my bubble tip anemone's!


INVERTEBRATES Are Trustworthy Friends For Aquariums

In addition to your personal efforts in maintaining your aquarium, you can also get help from a team of invertebrates who will work quietly without any expectations. If you know them well, you can realize how valuable their support is in maintaining the natural environment in your aquarium.

There are a number of invertebrates who are friendly to your fish and will happily live in the aquarium. Let us the list them on the basis of functions they perform.

There are mainly three types of functions which the invertebrates perform - the control of algae, the sifting of sand and detritus control.

Red-knobbed Starfish Protoreaster linckii at B...
Red-knobbed Starfish Protoreaster linckii at Bristol Zoo Aquarium, Bristol, England.
 (Photo credit: 

Controlling the algae
You can use snails, sea slugs and crabs for controlling algae in a salt water aquarium. There are a number of snails which can be used for this work. Astraea snails and turbo snails are important amongst them. They come from the Turbinidae family. This is most common family of snails. Both types of snails look similar. Their shell will be conical and smooth. It will look like a turban.
Now the question is how to identify them? Well, it is easy. Just look at their operculum. This is the door which these snails use for closing the shell. It is brown in color.

These snails are algae grazers. However they cannot eat all types of algae. So you should add other snails and crabs to control other types of algae. Some of them are - sea hares, emerald crabs and lettuce slugs. Out of these, sea hares can be the best choice for controlling algae. Emerald crabs are considered to be somehow rare in the world of crabs. But they are very famous for doing their job faithfully.

The work of sifting the sand
For this work your best choice is sand sifting starfish. Tiger Tail Cucumbers are also a good option. They are recommended if you have a bed of sand in the aquarium. They grow up to an inch in length and they live for a long time. Sand sifting starfish will clean up the sand. The only bad thing about them is - they will eat up everything in the sand, including the good stuff.

Tiger Tail Cucumbers will literally vacuum the sand. They will consume bacteria and micro-algae, making it sparklingly clean. The only thing you have to ensure is a reasonably big size aquarium. If the size is small, say less than 60 gallons, there is a risk of water getting toxic due to the waste created by them.

The control of detritus
It includes the particles of food which are left over, the waste of the fish accumulated in the aquarium etc. You can rely on many animals for controlling detritus - Bumble Bee snails, Sally Lightfoot Crabs, Scarlet Reef Hermit Crabs and Cerith Snails. You can make a combination of any of these animals for creating an effective team of cleaners and caretakers of your saltwater aquarium.

    By Chintamani Abhyankar
    Chintamani Abhyankar is a goldfish enthusiast and has been raising and breeding goldfish for many years. He is an expert on their care and an advocate for raising healthy goldfish the natural way.
    Article Source: EzineArticles 


Chaetopterus: The PARCHMENT WORM

Chaetopterus also known as parchment worm or parchment tubeworm is a member of the phylum Annelida. The parchment worm is a marine polychaete worm that dwells in the tube which it constructs by sediments or attaches to any coral reef substrate. It is known as parchment worm because of the parchment type of tube the worm makes. 

They are filter feeders and the adults dwell completely throughout their entire lives in the tube unless and until the tube is destroyed or damaged somehow. The young ones feed on planktons which is a typical feature among the phylum Annelida.

Sabellidae sp. (Feather duster worm) with radi...
Sabellidae sp. (Feather duster worm) with radioles extended (Photo credit: Wikipedia)
The tubes of the worms are either attached to the rocks or are present in the sandy bottom near the shallow waters. The body of the worm is thrown into segments and the whole body is provided with spines which are used for tunneling while the worm is busy in making the burrow.

The worm is known to make a U-shaped burrow in which it finally lives. The tubes are lined with mucus. The tubes measure 85 cm in length and 4 cm in diameter. The center of the tube is the widest area. The worm is highly specialized among the polychaetes as the middle segments of the body bear highly specialized parapodia adapted to participate in filter feeding. The parapodia are large in size and are fan-shaped which are used to create suction and pump water through the tube. The morphology of parapodia is used in the identification of species. The worm feeds by using specialized structures present on the mid-body segments that secrete mucus for trapping the food particles. A flow of water is created by three circular flaps on the three segments that creates suction and draws water towards the tube.

They lack any organ capable of detecting light as the worm passes its entire life buried inside the tube. Apart from this sort of habitat few species are known to exhibit bioluminescence. When the worm is disturbed in its burrow it moves away from the point of disturbance and secrets mucus towards the disturbance point which crystallizes and emits bioluminescence of blue colour. Two species of filter feeding crabs belonging to two different families are known to dwell in the tubes of these worms.

Apart from these two species a third one is also known to inhabit the worm's tube sometimes.  Polyonyx and Pinnixa are most frequently found to dwell in the tube of the parchment worm. They may be present together also. The breeding pairs do not share the tube with crabs and other species of animals. The crabs generally tend to dwell in the tubes and leave the tubes only when disturbed.