KEEPING VAMPIRE CRABS WITH MOURNING GECKOS - IS IT A GOOD OR BAD IDEA?
Mourning Gecko by @MillenniumSnakes
Ever since Dr. Plants on YouTube released his original video, a lot of people have started emulating this setup, believing it's a good cohabitation option. But is it actually a smart idea? And what are the potential downsides of keeping Vampire Crabs with Mourning Geckos?
As with most things in the hobby, there are a lot of factors to consider, and unfortunately, there aren’t many real benefits to this pairing. We'll break down the details below.
Vampire Crab & Mourning Gecko Cohabitation difficulty levels
Early on: Easy
Long term: Difficult
By the time you get to the end of this guide, you will understand why we have used this rating system.
Species Overview
Vampire Crabs (Geosesarma spp)
Origin: Southeast Asia (Indonesia, Borneo, Malaysia, Thailand, and many others)
Size: Up to 1 inch (2.5 cm) across carapace
Habitat Needs: Semi-terrestrial; requires both land and freshwater areas (spends 99% of its time on land)
Diet: Omnivorous scavengers; eat insects, fish food, decaying plant matter
Temperament: Territorial, especially males, semi-aggressive (some species more than others).
Geosesarma Dennerle (Purple Vampire Crab)
Mourning Geckos (Lepidodactylus lugubris)
Origin: Tropical regions worldwide (Pantropical) It’s also an invasive species in quite a few countries.
Size: Up to 4 inches (10 cm)
Habitat Needs: Arboreal, prefers vertically oriented enclosures with high humidity
Diet: Insectivorous and frugivorous (e.g., fruit mixes, small insects)
Temperament: Fast, skittish, and parthenogenetic (all-female and reproduces asexually)
Mourning Gecko by @MillenniumSnakes
Why People Consider This Cohabitation
Following a popular trend: The majority of people who want to keep this combination are following what they have seen popularised online, especially on YouTube.
Similar environmental needs: Both require high humidity, warm temperatures, and tropical setups, which makes them seem like a good combination. Which does sound perfect on paper. BUT! There are a few important things you need to know, so continue reading.
Space efficiency: Combining species may seem like a way to make the most out of vertical style tanks. Geckos live in the upper areas, and crabs stay down low. Sadly, this is a myth, and both species will use 100% of the tank.
These perceived benefits often ignore deeper, more serious considerations.
Key Issues with Cohabitation
Habitat Zones
Vampire Crabs: Most geosesarma species are semi-aquatic and require at least 20% of their environment to be water. However, they still spend 99% of their time on land, usually burrowing into the soil. Though they will roam the entire tank from top to bottom, especially at night, so they will have an environmental overlap with all other inhabitants.
Mourning Geckos are arboreal, and they do like to spend more time in the upper vertical areas of their environment, however, they will also use the entire tank with the exception of the water area.
Why it matters: At night, both species become more active and will encounter each other constantly. While there isn’t a major issue with aggression 90% of the time, that's not the key concern with pairing Mourning Geckos with Vampire Crabs.
Exo-Terra 45×45×90cm Vampire Crab Ecosystem
Predation and over population
Vampire Crabs are micro-predators and will attack small or young geckos. This is good for gecko population control, but ultimately, they won’t consume enough geckos to save you from a major overpopulation crisis.
Mourning Geckos, being small and fast, will find and eat baby crabs, and since vampire crab young take an extremely long time to grow up, the chances of them surviving to adulthood are quite small. Even in really complex, detailed tanks.
Bottom line: On a long timeline, this will cause a major imbalance in favour of the geckos will which breed x50 faster than the crabs can, ultimately dominating the tank and making life very stressful for the crabs. When this happens, you will see fewer of the crabs and more of the geckos.
Vampire Crabs also self-regulate their population with cannibalism, so keeping them in a species-only tank, you will rarely have overpopulation issues. Geckos, on the other hand, will reproduce to the point that you will be overrun with them which can cause your ecosystem to collapse. Then you’ll have to figure out what to do with all of the extra geckos…
Selling them is an option, but you might find it difficult to offload them.
Mourning Gecko by @MillenniumSnakes
Are There Any Situations Where It Might Work?
It’s one of those situations where it works all the way up until it doesn’t. Early on, there aren’t any real issues, but after a while, all of the issues mentioned above will start to happen. So you need to be prepared for what is to come six months to a year down the track. In practice, very few setups manage this successfully long-term, and even then, it's more of a novelty than a sustainable husbandry strategy.
The only way that keeping these two species together is successful long term is if you plan to be very hands-on in controlling the mourning gecko population. Either by selling them, or if they are a food source for another species you are keeping. That might sound rather brutal, but there are a few species of snakes that have a diet consisting of geckos.
As for the crab population, you will have to be quick to collect any baby crabs you find roaming your tank and isolate them in another enclosure until they are big enough to go back into the main tank. Again, not all of the babies will be eaten by the geckos if you have a really well-designed tank, but the mortality rate is extremely high.
Conclusion: Is It a Good or Bad Idea?
Bad idea for most keepers. While it might look cool and seem harmonious on the surface, things start to change over time. So, if you care about the long-term health and well-being of your animals, it’s better to house them separately and design each habitat to perfectly suit its inhabitants. I wouldn’t get mourning geckos unless you have a plan for all of the clones they produce!
Alternative Ideas
The best way to keep vampire crabs is in a species-only tank that is specifically designed for them. This includes a clean-up crew of springtails, isopods, worms and snails. If you have a big enough tank, you can consider adding shrimp and fish, but once again, there are some important things to consider if you choose to add either. Both of the guides below cover those topics in more detail, so check them out next.