If you are looking for something unique to add to your home aquarium other than fishes, then the Matano Crab (Syntripsa Matannensis) is the perfect choice for you. This crab species is active, beautiful, and has a distinctive behavior/appearance. Don’t you think it’s time to choose this wonderful crustacean as your aquarium pet instead?
In this article, I will explain everything you should know about the Matano Crab and how to care for them in the aquarium.
The aquarium trade of this species is rising due to its remarkably shaped purple chelae and unusual color. There have been continuous exports of this species to aquarium markets for the past 20 years.
Quick Notes about Matano Crabs
|Blue Matano Crab, Blue Crab
|Fully aquatic crabs
|Tank size (minimal)
|20 gallons (~90 liters)
|Size of the carapace
|3 – 6 cm (1.5 – 2.5 inches)
|Size across the legs span
|7 – 12 cm (3 – 5 inches)
|26 – 30°C (~77°F – 86°F)
|7.8 – 8.2 (7.3 – 8.5)
|4 – 8 (3 – 10)
|6 – 8 (4 – 12)
|100 (50 – 150)
|Less than 20 ppm
|Omnivore / Carnivore
|Aggressive / Territorial
|up to 3 years
Origins of Matano Crabs
According to taxonomy, this amazing creature can be scientifically classified into:
- Kingdom: Animalia
- Phylum: Arthropoda
- Subphylum: Crustacea
- Class: Malacostraca
- Order: Decapoda
- Family: Gecarcinucindae
- Genus: Syntripsa
- Species: Syntripsa Matannensis
The Matano crab (Syntripsa Matannensis) is known from quite a number of localities around Lake Matano in South Sulawesi, Indonesia, where it appears to be evenly distributed throughout the lake and cohabitates with other freshwater crabs like the Panther crab (parathelpusaa pantherina) .
In essence, the name ‘Matano’ was derived from the Lake. Matano Lake is of tectonic origin, which accounts for its extraordinary depth.
Natural Habitat of Matano Crabs
This species is mainly common in the sandy and rocky floors of Lake Matano which is its natural habitat and has a surface area of about 164 km². The Matano crab can be observed during the day wandering and feeding on snails and other organic matter on the open lake floor.
Note: Endemic crabs in Lake Matano are more found in the southern part of the lake than in the northern part because the southern part of the waters is not steep with a sandy bottom.
Recently, this species was categorized as endangered by IUCN Red List because the natural habitat is in a decline due to pollution from nickel mining operations on the shores of the lake, habitat destruction, and threats from non-native species.
The harvest of this species with no exception to its gravid females by local human populations for food or export for the aquarium trade and commercial fishing activities are major threats to its natural habitat.
Description of Matano Crabs
- Bright purple coloration.
- Large purple square carapace.
- Ambulatory legs of normal length, the second pair is the largest.
- Large powerful chela.
- White pigmented joints.
- White eyestalk.
- Inflated branchia regions.
- The suture between thoracic strenites.
- Shallow cervical groove.
- Unequal chelipeds.
- Cheliped finger with large molariform teeth.
- Dorsal margin of merus with slight cristae.
- Distinct t-shaped abdomen.
Matano crabs are fully aquatic and are not mainly dependent on a source of dry land. However, they are not afraid of and are capable of leaving the water so they should be adequately cared for to prevent escape from the aquarium.
These crabs are often 1 – 2 inches or 2.5 – 5 cm (purchase size) during their young ages and maxes out to over 3 – 5 inches (7 – 12 cm) across the legs span. The average size of the carapace width is about 1.5 – 2.5 inches (3 – 6 cm).
Once a proper aquarium is set up and optimum living conditions are met, this species can grow, reproduce and live up to 3 years.
The Behavior of Matano Crabs
Matano crabs are a little bit aggressive and tend to show this when kept in close proximity to small fish and snails. They are nocturnal animals, hence their activeness at late hours.
Matano crabs are territorial, especially males. They will not tolerate fellow members of their own species.
They are great climbers, it is vital to keep most openings sealed off as they won’t hesitate to climb out if the opportunity presents itself.
Matano Crabs Molting
Like other crustaceans, Matano crabs shed their exoskeleton as they grow. The frequency of molting depends on the age of the crab. For example, for fully-grown crab, this process occurs every 8 weeks, which implies shedding their exoskeleton.
During this period, the crabs will display signs of decreased activity and even less association with other tankmates. It is advised that you do not touch the crab as they are very vulnerable at this point and may die if disturbed. Once done with molting, they will eat their old exoskeleton to provide them with nutrients for the formation of a new exoskeleton.
|Note: Matano crabs need calcium to mineralize (harden) the shell. Calcium is vital for good shell growth. I highly recommend reading my article “How to Supplement Shrimp and Snails with Calcium”.
Identifying and Sexing Matano Crabs
At the same age, the body size of Matano males is relatively bigger than females. Males also have bigger claws compared to females.
Feeding Matano Crabs
Make it a priority to feed the crabs a well-balanced crab diet to ensure complete nutrition and optimum growth.
The Matano crabs are omnivorous scavengers by nature, they are not picky and will eat all sorts of food ranging from dead fish to decaying organic matter. You won’t have a hard time thinking of what to feed them as they can also feed on frozen food, bloodworms, and calcium supplements to help maintain the health of their shells.
To make the best feeding decisions, you should watch carefully to study the kind of food they enjoy most and the ones they do not eat. Bear in mind that you are not meant to overfeed them.
To improve their coloration, provide them with Hikari products (for example, Hikari Tropical Crab Cuisine (links to check the price on Amazon)). One of the main components of their food is astaxanthin. The balanced formulation offers necessary nutrients that promote proper shell development as well. You can read more about it in my article “How to Enhance Shrimp Color?”.
Also, feed them only once a day or two and make sure to remove uneaten food after 24 hours to prevent foul smell and mould build-up which can mess up the aquarium.
Note: Always thaw frozen food properly before feeding it to the crabs.
Note #2: Any medication that contains lots of copper should be avoided as copper is deadly to invertebrates. However, it is also necessary for the blood system. Read more about it in my article “How Copper Affects Dwarf Shrimp”.
Keeping and Housing Matano Crabs
When sourcing for Matano crabs its essential that you choose healthy active ones with their limbs intact and the normal bright color. Make sure you order from a reputable store to be certain you get a healthy one.
If you are planning to keep multiple crabs, make sure that they are females. A good setup is having one male to about 1 – 2 females. It can reduce the level of aggression.
Next up is setting up a proper habitat for the crabs.
You will need at least a 20- gallon capacity tank to house Manato crabs, some will want to opt for a 10-gallon tank but that would not be enough. It is best to get the biggest aquarium that can fit into the available space, that way the Matano crabs won’t be cramped as they grow / mature and there will be enough space to incorporate a variety of tankmates into the aquarium.
Note: The Matano crabs are known to be excellent climbers, escape artists, and active scavengers amongst other exceptional traits.
Substrate, Filters, etc
You should provide an air pump or a strong filter outlet to promote aeration. A sandy substrate at the bottom of the tank is preferable. To mimic their natural habitat you can also add some gravel or small rocks too.
Basic Tank Equipment (links to check the price on Amazon)
Before you put Matano crabs in the tank, make sure that the aquarium is well cycled and has had time to properly mature. Ideally, it would be better to use RO/DI water with the GH/KH+ re-mineralizers (read more here).
For the water, it is worth noting that Matano crabs like warm water temperatures between 77 and 86 degrees (26° – 30° C) and most notably a higher pH of 7.8 – 8.2. Use the thermometer to monitor the temperature of the water-filled section of the tank. You may need a heater if the aquarium is situated in a cool place.
Do not forget that they need careful acclimation (read more about it here) as all invertebrates.
To replicate the conditions of Lake Matano, and control the quality of your water, you need to use RO/DI water and remineralizers (Salty Shrimp Sulawesi Mineral 8.5 and Salty Shrimp Mineral 7.5 check the price on Amazon). Unfortunately, this is the major mistake when it comes to keeping Matano crabs.
Matano Crabs and Suitable Tankmates
Matano crabs can be a bit aggressive and will attempt to feed on slow-moving fish. If you must pair them with tankmates then you should look out for fast-moving ones. You can consider having the following as its tankmates:
- Bettas catfish
- Other tropical fishes
Nonetheless, be ready that from time to time Matano crab will find its opportunity to catch one. Basically, the same can be said about dwarf shrimp (for example, Cardinal shrimp (they also live in Lake Matano).
Finally, keeping them with snails will be a bad idea.
Although in the wild, Matano crabs share the same Lake with Panther crabs, I would not advise keeping them together as well. The size of your tank will not allow them to ignore each other and they will fight.
The Matano crab is indeed an interesting addition to your home aquarium. They are great scavengers and will work hard at keeping your substrate clean. This species is very active, easy to care for, and has a long lifespan of 3 years, which is awesome if you ask me.
However, their aggressive nature limits options if you want to keep them in a community tank.