Sulawesi Harlequin Shrimp (Caridina spongicola)

The Sulawesi Harlequin Shrimp is one of the smaller species of Sulawesi Shrimp, and they have a very striking and unique pattern. These shrimp are extremely shy until they are comfortable with their new environment. Once they have settled into the aquarium and do not fear predators, they will come out more, and its colours will show. It is an excellent addition to the community tank.

It is recommended that you keep these shrimp in groups of at least 15 as they will feel more comfortable and safer in more significant numbers and follow each other when eating. They continually scavenge the substrate, rocks, and plants for algae and food and display social behaviours. These social behaviours are often quite interesting to watch.

The Harlequin Shrimp possess very distinct colourations they have a red- and white patterned bodies and their legs and feelers have bands of both red and white along their lengths. These shrimps eyes stalks are red, and the eyes themselves are black and relatively large. The carapace has three red stripes running across it, with the final one being at the base of the tail, with red colouration running halfway along the top of the head, from the tip. The tail is red both on the top and bottom displaying a white band along each side.

Habitat

The Sulawesi Harlequin Shrimp are native to Lake Towuti in the Malili Lakes system in Sulawesi in Indonesia in Southeast Asia.

In the wild, they strictly live on and sometimes dwelling inside the oscula of an undescribed freshwater sponge of the suborder Spongillina making it one of only two known commensal freshwater species shrimp.

These shrimp typically hide between small rocks in shallow water and between large rocks in deeper waters. This shrimp is known to be intolerant of temperatures lower than 25.5 degrees Celcius, killing them.

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Diet & Feeding

It is beneficial if you keep your Harlequin shrimp on a varied diet to ensure optimal health. They are constant grazers of algae, but you should then supply them with substitutes such as algae wafers, shrimp pellets, or a crushed flake if this is lacking in the tank. Giving them an occasional meaty treat is also beneficial.

These shrimp are relatively small so remember this when choosing what food to give them. It would be better to feed these shrimp when it is dark and try not to overfeed them, providing only what they can devour within two to three hours.

Sexual Dimorphism

It is incredibly challenging to differentiate males from female Sulawesi Harlequin Shrimp. Unfortunately, no one has figured out how to do it with the naked eye because this species' males and females seem to look exactly the same.

The females have a saddle under the carapace that shows the eggs. However, the only way to see this saddle is through infrared light. With the shrimp's outside shell being so dark, you cannot possibly see the saddle without special equipment.

Breeding

Harlequin Shrimp will breed in the home aquarium, providing they have ideal water conditions and a suitable diet.

There is no larval stage for the Sulawesi Harlequin shrimp. The female will carry her eggs that are a reddish colour between her swimmerets for approximately 20 to 28 days. If there are no significant issues, they will give birth to shrimplets, miniature versions of the adults. The offspring immediately shows the same colouration as the fully grown shrimp just not as intense initially.

The baby shrimps growth rates are quite fast providing the tank is well maintained and in good shape.

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