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Captive Breeding Hermit Crabs

Updated: Apr 14

It is impossible to breed Hermit Crabs in captivity without having a science degree and a lab set up. WRONG! This is one of the biggest myths in the Hermit Crab owners community across the world.

Time and time again, we see people shutting down Captive Breeding, mentioning it is not humanly possible.

Oh how wrong they are. How do we know? Because WE DID IT! And so have many others worldwide. Natalie Van Amstel, Sue Brown, Mary Akers, Darcy Madsen, Stacy Boltz, Tammy Weick, Tiffany Boer.. just to name a few.

What was once thought impossible, has now been proven as doable, groundbreaking science. But, not by scientists. By at home Hermit Crab Owners.

The truth is, it is not easy, it is not for everyone. It takes extreme dedication, precision, time, patience, and failures.

But, the most important thing is, it is doable! And one day, it will pave the way for a new Hermit Crab trade, one that does not take them from the wild and torture them, but one that safely breeds them in captivity, brought into a loving, caring environment from birth, making their way into captivity a much friendlier experience.

Common Myths about Captive Breeding

• You need a science lab and degree

This is so far from true. Even scientists in their labs have not been able to figure out the Captive Breeding secret. If your Hermit crabs are willing to mate, you can breed them. It does take near perfect conditions for this to happen and the process of getting them from zoea to land is a tough one. But it is certainly doable in your very own home.

• Hermit Crabs don't mate in captivity

For a long time this was thought to be true. But as education on these species has increased every year and owners are setting up correct tanks better than ever before, Hermit Crabs are finally becoming comfortable enough to breed in captivity.

• Only experienced owners will have zoea spawn

Breeding has nothing to do with the owners experience, it has more to do with the environment the owner has provided for their crabs. It could be their very first summer of owning crabs and their crabs may breed. It is after all, upto the crabs if they will breed or not. Its upto you what kind of environment you provide for them.

You must isolate a female who is carrying eggs

Definitely not. This will only cause her more stress and she may drop her eggs in the sand to die. If she has happily mated within your main tank, it is best to leave her there. Moving them between tanks only causes unnecessary stress and could result in the loss of eggs.

Eggs come before mating

No, your females do not carry around eggs waiting to be fertilized. Only after mating does the female lay her eggs.

If the female has eggs, they will definitley spawn

Sadly no. Sometimes the females will dump their eggs on the sand. This may be caused by stress. Unfortunately if this does happen, they will not be able to spawn. You can however leave them on the sub and other crabs will consume them (gross I know)

This blog post centers around the breeding process and life cycle of the Coenobita Variabilis (Australian Land Hermit Crab)

Hermit Crab Life Cycle

The journey from spawning to becoming a Land Hermit Crab, takes around 14 days for the Coenobita Variabilis species. We have a much faster spawn to land cycle than that of other Hermit Crab species.

Mating -

During mating season, usually in summer (often between October-March) the female Hermit Crab will start to let off mating pheromones to let nearby males know that she is ready to mate. This is when interested males will approach the female and will start to portray guarding behavior. Mating will only ever take place if the female allows it, many males will show interest in mating with her, and will often fight over who will be successful, but eventually it all comes down to who the female chooses.

The male will approach the female and gently rock her shell back and forth, while tapping or stroking it to encourage her to come out. The female will partially come out of her shell, and this is when the male and female will hold each other, face to face and engage in copulation. With both hermit crabs partially out of their shells, the male will press his sex organs up against the females gonopores (female sex organs) and will release his sperm to go on and fertilize her eggs. Hermit Crabs will always mate within their shell for safety reasons.

Gestation -

The female hermit crab will carry up to a thousand fertilized eggs for about a month as they mature, these are held inside her shell, against the left side of her abdomen. Her pleopods (feathery appendages) hold the eggs safely inside her shell until she is ready to drop them in the ocean (or salt pool).

Eggs will appear orange/red in color for the first few weeks, but as they get closer to their spawning date, they will start to turn grey.

Spawning - Spawning of Zoea takes place in marine salt water. When the female is ready for her eggs to hatch, she will make her way into a body of marine water (your salt pool). Here she will use her legs to gently pull the eggs from her shell and toss them into the salt water.

As soon as the eggs hit the salt water, they burst open and the Zoea have spawned! Now begins their tough journey as they go through 3 more stages before finally making it to land to graduate as Land Hermit Crabs. Up until their journey to land, their lives take place entirely in marine salt water.

This is when it is time to move your new Zoea to their Kreisel tank. Ideally you would already have your Kreisel tank built and ready to go, however Zoea's can survive in the main tank pool for 24 hours before needing to be moved to the Kreisel.

Zoea Stage 1 - The very first stage of a Hermit Crabs life, Zoea stage 1. This is the stage after spawning. At this stage, they look like tiny white/translucent tadpoles. Within a few days they will start shedding and move to Zoea stage 2.

Zoea Stage 2 -

Your Zoea have successfully shed and graduated to stage 2! This is a step forward for your little Zoea's. You can tell your Zoea have shed as there will be sheds in the water.

Megalopae - On day 5 you can start to expect Megalopa, this is when your little Zoea's are finally starting to look more like crabs and less like tad poles. Their appearance will be that of a tiny lobster, you can see their little legs and claws. Now the real fun begins! Affectionately known as "Megas" they will now want to eat ALL. THE. TIME. If they are not fed, they will cannibalize their siblings with no second thought. It is important to keep them well fed at all times. Not every Zoea will make it to Megalopa stage and will unfortunately pass away if they do not evolve.

Shortly after becoming Megas, they will start to search for their very first shells in their Kreisel, this is something you will need to supply. Now is the time to set up a Transition Tank. This will be the tank that your shelled Megas will go into to make their way to land.

Shelled Megalopae -

Congratulations! You just hit the next milestone in your captive breeding journey! Having your Megas take their very first shells is a huge achievement in itself. Once your Megas have chosen their first shells, they will start to wander around the bottom of the Kriesel tank looking for a way out, often they will start to climb the bubbler. This is a sure-fire sign that it is time to move them over to their transition tank.

Juvenile Land Hermit Crabs

Once they have been placed into the salt pool of the transition tank, the journey is up to them now. Slowly they will make their way to land, in which they will begin to dig down into the substrate to begin their very first moult. This is a very quick process as the megas are so tiny, it can happen overnight or in a few days. You will know when your shelled mega has resurfaced as a land hermit crab as their colouring will change, they will appear slightly darker in colour, no longer transparent anymore, often taking on an orange/light brown appearance.

Kreisel Tanks

A kreisel tank is a specially built tank for raising Hermit Crab Zoea. Kreisel translates to spinning. And that's exactly the purpose of a kreisel tank. To keep the zoea and megalopae continually spinning and swirling around.

Zoea need constant movement to keep them alive and help them to shed. By having your kreisel tank water constantly moving, this mimics the ocean (the natural place for zoea to be spawned)

A kreisel usually consists of 3 compartments, 1 main compartment that houses the filter and water heater, and 2 seperate compartments that house the zoea and have the water continually circling.

To mimic the ocean, kreisel tanks must be filled with Marine salt water and prime. Fresh or still water will not work, and the zoea will not survive.

There are two ways to create a kreisel tank. You can either build a proper kreisel from scratch, or you can build a makeshift kreisel; often referred to as the coffee jar method. As I have not had the chance to build my own custom kreisel just yet, I will run through the easier Jar Method below.

Coffee Jar Method Kreisel

This is exactly as it sounds. You will be using coffee jars or large cylinder vases. You will need the following equipment to set up the jar method.

• 40L tank minimum (mine is 60L)

• 2 x large coffee jars or tall cylinder glass vases. If you can hold 4, that's even better!

• Aquarium water heater

• Aquarium water thermometer

• Air pump

• 2 x Airstones

• Airline

• Prime

• Marine salt

  1. Place the 2 jars inside the tank and fill the tank with regular warm tap water. You will need to make sure the water inside the main tank is sitting around an inch from the top of the jars. You do not need to Prime this water or add any salt into it. No zoea will ever be in this water.

  2. Place the water heater inside the tank, you want to heat the water AROUND the coffee jars to 28.c degrees and keep it there. If you get an adjustable water heater, set the temperature to 28.c.

  3. Stick the thermometer inside the main tank on the glass so you can keep track of the water temperature.

  4. Fill both jars with Primed, marine salt water. Do not fill them too full, but atleast to the brim of the jar (not to the top edge of the jar)

  5. Connect your airstones to the airline and airpump and place one air stone into each jar. The placement of your airstone is important. You want to create a whirlpool effect. This can be done by placing the airstone at the bottom of the jar and off to the side.

  6. Now that your kresiel has reached a temperature of 28.c degrees and your bubblers are in full swing. Your kreisel is ready for zoea!

The jar method is a fantastic makeshift kreisel for beginners, or those who are not expecting to have zoea spawn, but find themselves with a surprise batch of zoea anyway.

Captive Breeding Checklist

Let's run through the things you should have available on hand if you decide you would like to start Captive Breeding.

• Supplies for a makeshift kreisel tank (listed above)

• Ammonia Water Test Kit

• API 5 in 1 Water Test Strips (Saltwater)

• Cuttlefish Bone Powder

• Pipettes (lots!)

• Tiny Shells (think Shell Grit small)

• Aquarium Syphon

• Spare 20L Transition Tank

• Spare Clear Containers

• Prime

• Marine Salt (so much marine salt!)

• Small Transition Pools

• Spare Substrate

• Large Water Bucket (with lid)

• Spare Aquarium Water Heater

• Spare Aquarium Thermometer

• Refractometer

• Spare Thermometer/Hygrometer

• Spare Heat Mat

Foods for Megalopae

• Frozen Bloodworms

• Marine Snow

• Phytoblast

• Reef/Coral Foods (Reef Roids)

• Cuttlefish Bone Powder

• Bottom Feeder Pellets

• Betta Fish Pellets

• Live Phytoplankton Nannochloropsis

All of the items listed above will come in handy during your captive breeding journey. Having them readily available on hand will make your experience a lot more smoother, rather than awaiting their arrival in the mail or running all over town when you need them right then and there.

Finding your first Zoea

So you've found your first spawn of zoea in the salt water pool. Congratulations!! What an extremely exciting time.

Now comes the real work. If you already have a kreisel setup and running, you can move your zoea over straight away. If you don't, and these zoea are a complete surprise. Don't stress! The zoea can survive in the tanks salt water pool for upto 24 hours as long as you have bubblers/water movement.

Be prepared to lose some overnight tho.

If you don't have a kreisel setup, you can quickly throw together your makeshift coffee jar kreisel following the instructions above.

When it is ready, running and at the perfect temperature. Now you can move your zoea across.

The easiest way to do this is to remove the salt water pool from the tank and place it somewhere sturdy like the kitchen table or bench. You might want to grab a seat for this next part, it takes a long time and alot of patience.

Grab one of your coffee jars from the kreisel and place it within close proximity of your work area. Using your Pipettes, you will need to pipe (suck up) every single live zoea that you see in your salt water pool.

We highly recommend counting each zoea you suck up so you know what number you are starting with (be prepared that this number will dwindle drastically within the following weeks) gently pipe each zoea up and drop them into the coffee jar kresiel. You will notice some dead zoea in the bottom of your pool, they usually appear to be white in appearance and there is no movement. A healthy zoea will be translucent and have little black eyes with active movements. If you happen to have rocks or pebbles in the bottom of your salt pool, be sure to jiggle them around or remove them to find any hidden zoea. You will want to make the most of your 2 coffee jars and try to divide the zoea between them so that there is plenty of room and minimal crowding.

Once you have added all living zoea to your kreisel tank. The hard work begins.

Day 1 (Zoea in Kreisel)

At this stage, your zoea will be actively thrown around in the water which mimics the ocean. Don't worry, this isn't too rough for them and it will help them to have their first sheds. We don't usually feed them at this stage. You will also notice them zooming around the jars, this is totally normal.

Day 2 (Water Changes Begin)

Now comes the hard work. A true labour of love. Water changes. Raising zoea is like attending to a newborn baby, except instead of nappy changes, you've got water changes.

The easiest way for water changes is to use a clear container, Aquarium Syphon and Pipettes.

To keep your water at consistent temperatures, some Breeders will make up a large bucket of Primed and marine salted water and keep an aquarium water heater in there to keep it consistently at 28.c. By keeping the water out of sunlight and a lid on the bucket, this will prevent evaporation.

Before they start shedding, we recommend 1-2 water changes a day. You will need to syphon out 2/3 of the jar water and replace it with fresh Primed and marine salted water. If you come across any dead zoea, remove them from the jars. They will only add to your Ammonia levels which we don't want. During water changes is a good time to check your Ammonia levels using your water test kit, and also using your API 5 in 1 Water Test strips to test the Nitrates, Nitrites and PH level.

Nitrites should always be 0

Nitrates should always be 0

PH levels should be 7.5-8 in their readings

Start by removing the first coffee jar and using your Syphon to suck 2/3 of the water out into a clear container. We recommend a clear container for this incase you accidently suck up any zoea. If you do happen to suck up live zoea, simply use your pipette to pipe them back into the kreisel jar.

If you see any dead zoea (white/pink in appearance) pipe them out of the jar and dispose of them.

Refill 2/3 of the jar with your batch of fresh marine salt water and replace the jar back into the kresiel tank.

Repeat the process with the second jar.

TOP TIP - If you are having a hard time seeing your zoea, shine a light on them using a torch or place the jars on a dark coloured towel during water changes.

Day 3 (Shedding & Water Changes)

By now, you may notice some of your zoea have started to shed. There will be "debris" in your kreisel, this is shed. A good sign and totally normal! Congratulations on your Zoea stage 2!

Continue with your water changes, if you are noticing your water dirtying quicker, up your changes to 3 times a day. Continuing with the method mentioned above. At each water change, check your levels (Ammonia, PH, Nitrites & Nitrates)

If you are noticing a spike in Ammonia, add Prime to the jars and change the water out often. Missing water changes can cause a spike in Ammonia.

If your PH levels are too low, try adding some calcium into your water. After experimenting with Cuttlefish Bone, Star Fish and Sea Urchins. I personally found adding Cuttlefish Bone Powder to the pools the most effective solution. But be aware, this will dirty your water quickly and will give it a cloudy appearance. It may call for complete water changes sometimes.

I personally recommend adding Prime to your water (1-2 drops) atleast 4 times a day, and continually checking your levels mentioned above (not just at water changes) * I'm abit of a helicopter Zoea Mum, so yes, I check things excessively throughout the day. Don't be alarmed if this is not something you can do due to work or life commitments.

Day 4 (Feedings & 3 x Daily Water Changes)

By now, you can start to offer your little zoea some foods such as Phyoblast, Marine Snow or Reef Roids. At this stage they won't be as hungry, but, Megalopae stage is on the horizon and once they hit that stage, they are ravenous!

Continue with your 3 x water changes a day, and continued level checks. If you find that Cuttlefish Bone Powder is helping the PH levels, add it to every water change and keep up with the Prime dosing. If your Ammonia levels build, the water becomes hardened, and in return will make it harder for zoea to shed and grow to that Megalopae stage.

Day 5 (Megas!)

Day 5 is usually when we expect to see Megalopae. This is a huge step forward and an exciting milestone! Now your Zoea have grown their crab claws, they will look like tiny translucent lobsters.

You will need to place all Zoea into one jar and all of the megas into the second kreisel jar. This will avoid the megas from consuming the zoea, and give the remaining zoea a chance to become megas.

Now is the time to really up your game with feedings and water changes. Expect the death toll to rapidly rise during this period as Megas become increasingly hungry and will turn to their siblings for a meal.

You should feed your megas multiple times a day using defrosted bloodworms, crushed up beta fish pellets, phyto blast, marine snow, reef roids, bottom feeder pellets etc. You can also offer them some pieces of fresh fruit. These will float on the surface and Megas will come to the surface of the water to munch on them.

I found Strawberry slices to be very popular. Remove these after a few hours as they will begin to spoil. The aim is to constantly be feeding your megas to avoid them eating each other. However, they will most likely still continue to consume their siblings.

Now is the time to turn down your bubblers so that the flow is not as strong, this will give your megas easier access to foods and shells. You will need to add in some small first shells for your Megalopae at this point. You can pick tiny whole shells out of shell grit and use a pin to clear the opening of the shell so they can access it. Place these at the bottom of the kreisel jar.

Now that you are adding food multiple times a day, the water will spoil much quicker. Continue your 3 x water changes daily and remove any uneaten foods. Megas will latch onto bloodworms and suck out their insides, so you should remove the bloodworm carcass when they have finished with it.

If you have reached day 5 and still have no Megalopae, don't stress just yet. Sometimes if the water is on the cooler side, it can take longer for Zoea to transform. Any Zoea that do not make it to the mega stage will sadly pass away.

Once you have all Megas, divide them over the 2 jars so their is less chance of cannibalism.

Day 7/8/9 (Megas may start to take shells)

By now, you should be keeping up with your 3 x water changes a day, continued water testing and multiple feedings. There should be no zoea left by now. They will either have turned Mega or passed away.

You may also notice some of your megas start to take on their first shells! This is a crucial step for their survival to land. Those who do not take a shell, will not move forwards to the next stage of life.

After a few days you will start to notice your shelled megas climbing up the airstone. This is a sign that they are ready to head to land and it is now time to move them to your transition tank.

Building your transition tank

A Transition Tank is where your shelled megas will make their journey to land for the very first time. And where they will continue to live for the next few months as they grow and mature.

Thankfully, this tank only needs to be small in size. You can easily get away with a 20L tank for this setup.

The following items are needed to set up a Transition Tank.

• 20L Glass Fish Tank with lid

• Heat Mat

• Thermometer/Hygrometer

• Playsand

• Coir Peat

• Prime

• Marine Salt

• Small Salt Pool

• Something to climb out of the pool (wood, ramp, mesh etc)

• Fake Plants

• Dry Sphagnum Moss

• Small, flat food bowl

• Small, flat shell shop

• Tiny transition shells

• Airstone

• Air Pump

• Air Line

Setting up your transition tank the correct way is very important. And quite different from how we recommend setting up your main tank.

Your substrate should be no deeper than 3-4cm, you want your babies to be able to dig down to moult, but too deep and they will struggle to resurface.

You will also need to make your substrate slightly damper than the usual substrate in your main tank. These babies are so tiny, they can not possibly dig through dry sand.

Because they are transitioning from life under water to life on the sand, it is important that we keep their temperature and humidity stable and higher than that of your main tank. We recommend keeping your temperature at 30.c degrees and humidity at 90%.

Your shell shop and food bowl will need to be as flat as possible and level with the substrate so that they can easily access their food and shells.

Once your transition tank is ready to go, it's time to move your shelled mega to the next phase. All shelled mega should be placed into the salt pool inside the transition tank. They MUST have a way out of this pool, using either wood, ramps, fine mesh etc and a bubbler to keep the water fresh. This is important so they can make their way to land. While in the transition salt pool, you should still be offering them foods that you were offering in the kreisel.

It usually doesn't take long for them to find their way out of the water and start their journey to land. You may find them very hesitant at first, coming out of the water and then going back in as they figure out where they need to go and what they need to do.

As soon as your shelled megas hit the sand, you've gotten them to land! BUT, the journey isn't over yet. They need to dig down, moult and come back up before you can say that you have successfully bred a Hermit Crab. When they first hit land, they are not classed as Land Hermit Crabs. Only after their very first land moult, do they come back with modified gills and are now a land hermit crab. Being as tiny as they are, their moults will not last long at all. Usually within 24 hours.

When they first retreated from the pools, you will have noticed they had a translucent appearance. Once they have dug down, moulted and come back, they take on a slightly darker and more solid appearance. Looking somewhat orange/light brown and their limbs are no longer transparent. Now you really do have captive bred Hermit Crabs! Congratulations!!

Be prepared that not all shelled mega in the transition pool will make it to land, some will drop their shells in the pool and will unfortunately pass away. Some in the kreisel tank may never take shells and will also pass away. Once you have all of your shelled megas to land and out of the transition pool, you will need to add in a small fresh water pool for them to drink.

Usually by now I remove the larger salt pool and add in a small salt and small fresh pool with fine plastic mesh for climbing in and out. You don't have to add bubblers to these, but it does help with water changes and humidity if you do.

You will want to entice your new babies to eat and to continue to eat various times a day to gain their strength. They have alot of moulting and growing to do now.

We highly recommend offering them foods that they ate while in the water stage of life. You must remember that food will smell different on land than it did in the water for them, so they may be hesitant to eat at first.

Foods to offer on land

• Cuttlefish Bone Powder

• Beta Fish Pellets - Crushed

• Bottom Feeder Pellets - Crushed

• Frozen Bloodworms - Thawed

• Greensand

• Worm Castings

• Reef Roids

• Pureed fruit such as Banana, Strawberry, Apple etc.

• Egg Powder

• Kelp Powder

• Oyster Shell Powder

• Spirulina

• Flaxseed Powder

• Shrimp Powder

You must remember that all foods offered need to either be in powdered form or mashed/soft (fresh fruits/veg) They do not have the capacity to break apart large pieces of foods.

Why didn't my babies survive after their first moult?

Sadly, there is only so much we can control. The rest is upto them.

Baby Hermit Crabs, Zoea and Megalopae are extremely delicate. Even the slightest change in the environment can harm them.

They may not have been strong enough to survive another moult, perhaps they dropped their shell and passed away. Things like temperature and humidity fluctuations can effect them too.

Captive Breeding is still so new, and every year breeders around the world are constantly learning new things about the breeding and raising process. No one knows the answers to all questions when it comes to the life cycle of these species.

All we can do is try again every year and keep track of what we did, what worked and what didn't.

A Gravid female with eggs. Photo belongs to HCA

A makeshift jar kreisel for zoea. Belongs to Sue Brown

Makeshift jar kreisel using flower vases. Bubblers have not been set up as yet. Belongs to The Happy Hermie

Zoea have spawned in the main tank salt water pool. Belongs to Sharyl Hodgetts

More zoea spawned in the salt water pool. Belongs to The Happy Hermie

Zoea in a kreisel jar during a water change. Belongs to The Happy Hermie.

Zoea close up, belongs to The Happy Hermie.

Megalopae in the kreisel. Belongs to Sue Brown

More Megalopae, belongs to Sue Brown

Tiny first shells picked from Shell Grit.

These will be offered to Megalopae. Belongs to The Happy Hermie

Megalopae checking out their first shells at the bottom of the kreisel jar. Belongs to The Happy Hermie

Megalopae in their very first shell. Belongs to The Happy Hermie.

Shelled Megalopae eating a thawed bloodworm. Belongs to The Happy Hermie

Shelled Megalopae climbing the bubblers. Belongs to The Happy Hermie

Building the transition tank with the salt pool and shallow substrate. Belongs to The Happy Hermie

Deep salt pool, shallow fresh pool, dry Moss etc for the transition tank. Belongs to The Happy Hermie

Shelled Megalopae making its way up the cholla wood to land. Belongs to The Happy Hermie

Almost to land! Belongs to The Happy Hermie

Two have finally made it to land and are starting to dig down for their first moult. Still translucent in appearance. Belongs to The Happy Hermie

First steps to land. Belongs to Sue Brown

A successful first moult, finally graduating to a Land Hermit Crab. No longer transparent, a light brown appearance. Belongs to The Happy Hermie

One week old Land Hermit Crab. Belongs to The Happy Hermie

Transition tank has been changed to accommodate our newest baby land hermit crabs. Belongs to The Happy Hermie.

Babies explore their new surroundings. Belongs to The Happy Hermie

Babies dinner. Strawberry, Spirulina, Greensand, Cuttlefish Bone, Beetroot Powder, Bloodworms, Beta Fish Pellets, Almond Powder. Belongs to The Happy Hermie

Photo shows just how small they are.

Belongs to The Happy Hermie.

Babies exploring their tank and eating.

Belongs to The Happy Hermie

10 week old baby. Belongs to Sue Brown

• Captive Bred Baby - Belongs to Sharyl

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