When taking care of a regular fish tank is no longer enough! 🤣
If you live in Calgary and are a pet owner, you've probably visited the Pisces Exotica Pet Emporium at least once. This massive, independent pet store has always been a favorite of mine since I moved to Calgary back in 2008. Their aquatic department is nothing short of impressive, with large tanks managed by their dedicated staff and employees. Many of these tanks are actually intricate ecosystems, known as vivariums and paludariums.
A vivarium is an enclosed space designed to provide a stable environment for plants and animals. It can range from a small container to a large, room-sized installation. Vivariums are often used to recreate specific habitats and can be classified into various types, such as terrariums (primarily for land-based plants and animals) and aquariums (for aquatic life). Vivariums are excellent habitats for reptiles, amphibians and insects.
A paludarium, on the other hand, is a type of vivarium that incorporates both terrestrial and aquatic elements, creating a semi-aquatic environment. It typically includes a water feature, such as a pond or a stream, alongside land areas where plants and animals can thrive. This combination allows for a diverse range of flora and fauna to coexist, simulating a natural wetland or rainforest habitat. Paludariums are great for amphibians, salamanders, turtles, crabs, snails and crayfish!
I have often been inspired to create a complex, self-sustaining ecosystem at home, different from my regular planted fish tanks and ponds. However, I didn't have the courage or motivation to start this ambitious project until my daughter fell in love with hermit crabs during our adventures in the Pacific Islands of Fiji last year. Her enthusiasm sparked a desire in me to build something unique and captivating — a paludarium for vampire crabs.
But you may ask, why not just get a few hermit crabs from the regular pet store? They are relatively cheap and easy pets for children. After doing a little bit of research, it appeared that owning hermit crabs raises several ethical questions - and they are not known to survive well out of their natural habitat, despite the greatest of care. Hermit crabs, often sold as low-maintenance pets, actually require very specific conditions to thrive, which are challenging to replicate in a home environment.
Vampire Crabs: A fascinating alternative!
The captivating Vampire Crab (Geosesarma spp.) is a colorful, semi-aquatic species native to Southeast Asia. They are named for their cool appearance, with unusual purple bodies and bright orange or yellow eyes, which give them a somewhat "vampiric" look. These crabs are small, typically growing to about 2 inches in width, making them ideal for home paludariums.
Unlike hermit crabs, Vampire Crabs are bred in captivity (and not stolen from the wild) and adapt well to life in a controlled, fresh water environment. They are omnivores, enjoying a varied diet of plant matter, small insects, and commercial crab food, making them relatively easy to feed and keep happy!
But it wasn't long before our family realized that the science and art of building paludariums for Vampire Crabs and the like was nothing like creating a simple aquarium. From tiny enclosures to massive elaborate tanks, there's no one-size-fits-all approach when it comes to paludariums. It all comes down to how much space you can allocate and how much money you can spend! During our research online, we have seen tank experts put together very complex ecosystems that likely cost thousands of dollars and took several days of work and preparation — requiring much more than just gravel and a few plants.
Our goal at this point was to try to make a paludarium at the lowest cost possible without compromising the quality of the environment.
Here's how our family approached this challenge:
Step 1 - Get a tank that can accommodate both a terrestrial and an aquatic environment.
As paludariums can come in many shapes and sizes, they can also vary widely in cost, especially if you want or need to have open doors at the front of the tank. We didn't specifically need this feature, so we decided to refurbish an older but still in perfect condition 55-gallon Marineland tank for this project - probably saving us up to $300. Most paludariums are usually on the smaller side in terms of surface area, so using this tank gave us a lot of space to work and be creative, allowing us to house a larger number of animals and plants within the ecosystem.
As Vampire Crabs are known to be escape artists and a paludarium must be maintained at a high humidity level, we had to figure out what to do for a tank cover. The original cover of the tank did not meet our requirements for light and coverage, and a mesh cover wouldn't adequately maintain humidity levels. Ordering customized glass or plexiglass was neither cost-effective nor safe.
So, we decided to purchase a glass cover from Pisces for $65. To allow for sufficient airflow within the paludarium, we used a piece of corrugated plastic covered with mosquito screen. This piece can be removed at will. This solution has been working well, and was made with scrap materials and stuff found at Dollarama.
Step 2 - Get a proper light fixture for the tropical and aquatic plants!
You can't have a paludarium without proper lighting. The small LED lights that usually come with a fish tank kit are rarely strong or adequate enough to ensure proper plant growth. However, external fixtures for planted tanks and vivariums, especially for a tank that is 48 inches long, can be quite pricey. We decided to go the second-hand route and buy a gently used $30 LED grow light on Kijiji (the kind people use for microgreens or aquaponics).
We didn't want the light fixture to sit on or touch the tank cover, or be exposed to the humidity coming out of the paludarium. So, we built a small shelf above the paludarium and using two metal rods, we suspended the light fixture above the tank. This setup also gives us the flexibility to adjust the height or even remove the light if needed. We are currently turning the light on and off manually every day but it will eventually be plugged in a timer to allow a proper light and dark cycle.
Step 3 - Prepare the filtration and heating devices for the aquatic ecosystem.
Before starting to put everything together inside the tank, we had to figure out how to keep the water in the aquatic ecosystem clean, clear and warm enough. Vampire Crabs love warmer water to molt and reproduce. Warm water is also essential to maintain a certain humidity level within the tank through evaporation, which is a significant concern in the dry Albertan climate.
We have noticed that many paludariums are constructed without a proper filtration system, relying mostly on plants, bacteria and frequent water changes to keep the water clean. However, we really wanted a system that would jumpstart the nitrogen cycle, and keep algae and organic waste under control.
We managed to create a simple filtration box by purchasing a small basket from Dollarama ($2), use a small underwater pump I had from a previous aquarium ($8-15), and some tubing from Home Depot ($13). The inside of the filtration box was filled with filtration media (see next step) to allow mechanical and bacterial filtration. The tube was run against the back of the tank to allow for a future fountain.
Finally, a small water heater from Walmart ($12) was installed horizontally above the filtration box.
Step 4 - Plan the layout with filtration foam!
As mentioned before, there is no one-size-fits-all approach to the layout of a paludarium. Many paludariums feature stunning, natural-looking backgrounds and walls that mimic stones or tree bark. These are often created using expandable foam or carved and painted styrofoam panels, which are then attached to the back and sides of the tank and sealed with silicone.
Given the size of our tank and our desire not to permanently adhere anything to the glass, we decided to forgo a background or wall feature (for now).
A significant challenge was figuring out how to properly separate the aquatic and terrestrial parts of the paludarium. Some setups rely solely on large stones, pieces of driftwood, or piles of rocks and substrates to build above-water sections. However, these configurations are not always suitable for growing traditional tropical plants or providing proper land for other organisms like springtails and isopods (more on these critters later).
Other paludariums use several inches of lava rocks and/or LECA balls to elevate the planted areas. However, LECA balls can be quite expensive, especially to fill a 55-gallon tank. They also require some physical support or barrier not to spill over the whole tank. Ultimately, we decided to use thick filtration foam pads, which are easy to cut and stack, while allowing water to flow and create an environment for beneficial bacteria.
As large sheets of filtration foam pad can be quite expensive, we ordered from Aliexpress for $80.
As you can see in the photos, we decided to place the water area in the middle of the tank and have two terrestrial areas on each side. We cut the foam pads accordingly (and with a small angle) and placed them tightly against the glass walls to eliminate any crawling spaces.
An important detail to consider when building a paludarium is ensuring that the soil used for the terrestrial part does not fall into the water or infiltrate the foam pads. To prevent this, we used inexpensive weed fabric from Dollarama ($3) to create a barrier.
Step 5 - Acquire the tropical and aquarium plants, soil and substrate, and the decor! Oh My!
With all the different sources of inspiration, it would have been easy to experience "decision fatigue" regarding how we wanted the paludarium to look like and what we needed to make it happen. Generally, paludariums are constructed with assorted rocks and stones, as well as driftwood and branches of various shapes and sizes. Believe it or not, these items can be quite expensive when purchased from specialty stores or ordered online!
In an effort to remain cost-effective, we started looking online for other tank enthusiasts who were selling or giving away their rocks, stones, and wood. Over the span of a few weeks, we were very successful in our efforts. We were able to collect a variety of pieces and took the time to properly sanitize and clean them to avoid introducing pests or algae into the paludarium.
For the substrate, we were able to purchase potting soil at a discount from Walmart (about $10), along with a bag of marine sand ($5), which is essential in a paludarium with Vampire Crabs. We also got some substrate (made from small pebbles) from Amazon ($18) to provide better grip for the aquatic plants under the water. Finally, we also ordered some coconut husks from Amazon ($9) to cover the land areas and create the perfect environment for the crabs and other little critters.
A paludarium wouldn't be complete without a variety of plants, both aquatic and terrestrial! Given the endless possibilities, we decided to keep things simple and cost-effective. There would always be time in the future to make changes and improvements if a plant didn't work out or grew well.
We secured a few aquatic plants via Facebook Marketplace at a fraction of the cost compared to pet stores ($20 in total), plus we avoided the risk of introducing pest snails. We also purchased lotus seeds on Marketplace ($15), which we started in a separate water dish a few weeks in advance. Vampire Crabs are known to enjoy floating plants a lot!
For the tropical plants, we visited Walmart, Golden Acres, and a local plant market on a few occasions. We spent about $30 in total on tropical plants, with the begonia being the most expensive. We decided not to use the fern in the end. Additionally, we ordered frog moss on Amazon for $15 to fill in the gaps.
Then we put it all together! 😄
It's important to note that we should have used potting soil or substrates containing no added fertilizers. However, as we are writing this, almost four weeks later, we have not detected any negative impacts other than the plants growing exponentially. Typically, the waste produced by the crabs and the "cleaning crew" (more on that later) should be sufficient to keep the soil well fertilized.
Step 6 - Take a leap of faith and add water!
After laying down the foam pads, soil, sand, aquatic substrate, driftwood, and rocks, the next step was to add the water—eeeek! This is a critical step because if something goes wrong, it would be a mess to remove everything. It's also important to be very careful not to splash water on the terrestrial parts or accidentally knock over the rocks (and risk scratching the glass or the bottom of the tank). We carefully filled the tank with about 6 inches of water and plugged in the filtration pump, and voilà !
Step 7 - Acquire your "cleaning crew" aka springtails and isopods, and shrimp!
You may be thinking: "alright, time for the crabs now" but not so fast!
In a paludarium, springtails and isopods play a critical role in maintaining a healthy ecosystem. These tiny bugs are often referred to as the "clean-up crew" because of their ability to break down organic matter. In a humid environment like a paludarium, there will be mold, fungi and organic decay at some point... 😫
Springtails are minuscule, wingless insects that thrive in moist environments. They are excellent at decomposing dead plant material, mold, food sources and other organic debris, helping to prevent the buildup of waste in the soil. By doing so, they promote healthy soil and prevent the growth of harmful bacteria and fungi. Additionally, their presence helps aerate the soil, which is beneficial for plant roots. We were able to get a culture of springtails from Pisces for $15.
Isopods, also known as woodlice or pillbugs, are crustaceans that play a similar role in decomposition. They feed on decaying organic matter, including leaves, wood, and even leftover food that the crabs didn't eat. Isopods help break down these materials into smaller particles, which can then be further decomposed by the springtails, and microorganisms. This process releases nutrients back into the soil, promoting plant growth. We were able to get isopods (Porcellionides purinosus "Powder Blue") on Kijiji for $10.
As for the aquatic portion of the paludarium, we decided to add a couple of cherry shrimp from a colony we keep in another fresh water tank. Cherry shrimp are good tank additions due to their algae control and detritus cleanup (plus they are super cute!). It is important to note though that shrimp are occasionnally on the menu for Vampire Crabs so it's a good thing that they can reproduce and move quickly.
Step 8 - Time for the Vampires to make their entrance!
Initially, we hoped to let the paludarium "run" without crabs for at least three weeks to allow the ecosystem to "balance" itself, the water to cycle, and the plants and moss to grow a bit. However, we had to speed up the process when we found someone on Kijiji selling the last of their baby crabs for a third of the price at Pisces (usually $30 each). We learned that the crabs with vibrant colors sold in pet stores are usually over a year old, which means they have less than a year left in their lifespan.
The five babies we acquired ($50 in total) are estimated to be about three months old and should develop their colors (purple or red) by next winter, and they may even start to reproduce.
The only issue so far is that because they are so small and nocturnal, they have been hiding most of the time, only making brief appearances in the evening... 😶 Two even molted in the water just a couple of days after arrival!
So far, we have been feeding them (rotting) pieces of fruits and vegetables, fish and shrimp pellets, algae wafers, and dried bugs.
Step 9 - "Work in Progress"
Now that the paludarium has been running for over four weeks, maintaining a good environment for its inhabitants is crucial. Here’s what we’ve been doing:
Performing a 50% water change twice a week to promote healthy aquatic plant growth and nutrient competition against algae.
Misting the paludarium with distilled water several times a day to maintain optimal humidity levels and keep the soil and husks moist.
Varying the food sources for the crabs daily to ensure a balanced diet.
Running a small fan above the paludarium to promote gentle airflow and reduce condensation on the glass during the day.
Placing a couple of gnat traps inside and outside the paludarium to control the gnat population, which should eventually stabilize as springtails compete for resources.
Our next steps:
Purchase a misting/fogger device to maintain adequate humidity levels.
Add more pebble substrates to allow deeper rooting for some of the aquatic plants.
Keep green algea in check by cleaning the glass and rocks frequently.
So there you have it, folks: the story of our DIY paludarium for baby Vampire Crabs! We're excited to watch them grow, become bolder, and explore their new home. We plan to publish an update in the next few months when they start showing their vibrant colors and unique personalities.
Feel free to reach out if you have any questions! 😎
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