The zebra crab; a crab that dares to eat the venomous spines of sea urchins and ride on them. The crab is expensive and hard to find in the stores though the craze of getting them has no limit. Another hard thing is finding information about them.
Despite having some different requirements zebra crabs are very easy to care for. Here you’ll get all the information you need to know to keep your zebra crabs healthy.
Quick overview of the zebra crab
| · Care Level | Easy |
| · Name | Zebra crab, Sea urchin crab |
| · Scientific name | Zebrida adamsii |
| · Temperament | Peaceful |
| · Breeding | Comparatively easy |
| · Approximate size | 2 cm to 2.5 cm (around an inch) |
| · Optimal temperature | 72-78°F (22-26°C) |
| · Diet | Omnivorous |
| · Sleeping nature | Nocturnal |
| · Life span | 2 to 3 years in captivity |
| · Reef compatible | Yes |
| · Color | light pink, dark red-brown, black and white |
| · Distribution and natural habitat | The zebra crab is spread through shallow water of the Indo-Pacific region; Indonesia, Singapore, Japan, Philippines, Australia, Western Pacific Ocean |
| · Depth | 18 meters |
Interesting facts about the zebra crab
- Sea urchins’ host: Like the harlequin crab depending on sea cucumber, the zebra crab depends on sea urchins, wears them and rarely comes out of the urchins. The crab does not pose any threat to the corals or any other fish, meaning they are completely reef-safe: the name sea urchin crab also comes from this.
- Appearance: The zebra crab has a typical black and white pattern that resembles the coat of a zebra. The crab kind of looks robotic which makes it unique, has a smooth carapace with spiny legs and claws and blends well in the spines of urchins.
- Unique Adaptability: The marine crabs can’t survive out of the water for long. The zebra crab despite being a marine crab, can be found almost out of the water.1
- Genus Zebrida: Three species found from the genus zebrida. Z. brevicarinata, Z. longispina, and the most common being Zebrida adamsii. All of them have 4 zoeal and 1 megalopal stages.
Care for the Zebra crab
Tank setup
Tank size
If you have only one zebra crab then don’t worry about the size, you can keep them in your old tank. However, the size matters when keeping 2 zebra crabs, so choose a bigger one (20 to 30 gallons minimum) with different territories for each including urchins. Keep in mind about the tank mates, the size of the tank, and the population should be considered.
Substrate
They do not have contact with the substrate, so which substrate you choose doesn’t really matter. Choose a good typical saltwater aquarium substrate like crushed coral sand or aragonite reef substrate.
Decoration
Decorate the tank with aquarium stones and corals and anemones, however, you like. They will not come out of the sea urchin let alone harming the corals.
Sea urchin for zebra crab
It’s obvious they will require sea urchins in the tank. 2 to 3 sea urchins for a crab and if there are fewer sea urchins like 1 for 2 crabs or two for two crabs will fight for limited space. Because they make their territory in urchins and don’t move much from it or come out except for moving from one urchin to another.
Choose bigger urchins always that are bigger than 3 inches as less than that size is not ready yet to host your zebra crab; also an urchin will grow faster without hosts.
The zebra crab is mostly found in the fire urchin, flower urchin, double spined urchin, star urchin, Salmacis sphaeroides, and Diadema urchin. Be sure urchins are one of them, also they prefer long spined urchins like Diadema setosum which provides them with protection.
Some of the urchins are venomous and extremely painful to humans like radiant urchins, that’s why many prefer nonvenomous urchins like fire urchins (they are also venomous; caution while handling).
It is considered they have symbiotic relations with the urchins, the crabs get shelter, and in return, they help clean the urchins by feeding on parasites and debris.
Water parameters for the zebra crab
- Temperature: 72-78°F (22-26°C)
- Salinity: 1.023-1.025 specific gravity
- pH: 8.1-8.4
- Ammonia/Nitrite: 0 ppm
Feeding of the zebra crab
In the wild, they basically depend on algae and detritus found in urchins’ surroundings. They’re suspected of feeding on their hosts’ spines, tube feet, and tissues as well as xenia and caulerpa. So they can be classified as parasitic instead of symbiotic.
Other things besides urchins and algae, you can feed them with flakes, pallets, and meat such as mysis or brine shrimp, and small pieces of fish or chicken. All crabs are omnivorous, so don’t worry about the diet limitation.
They may not like to eat the mentioned additional food and depend on urchins. In that case, you better keep a minimum of 3 urchins because one urchin that can’t heal fast will eventually die as it can’t repair its damaged cells caused by the crab’s eating. Some crabs prefer living on the same host throughout their lives and others frequently move between urchins.2
Also, you have to be cautious about sea urchins feeding.
Tank mates of the zebra crab
As they’re protected by the venomous urchin, so no one would dare to disturb them. So, almost all of the regular fish and crustaceans would be harmless. And about the zebra crab, they don’t care about the surrounding animals.
A pair of male and female would be best as they are mostly found in pairs in the wild.
If you are thinking the crab is wasting its space only riding on one urchin. Then you can think about bringing a pair of Coleman shrimp.
You can keep 2 other crabs the same as them; one is the harlequin crab which will need sea cucumber and the other is the venomous gaudy clown crab which depends on zoas. Each of them seeks different territories that’s why nobody will harm anybody.
