The jewels of Sulawesi

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There are shrimps, and then there are demanding shrimps. Gabor Horvath takes the plunge with some of the trickiest freshwater offerings around.

It’s always encouraging to see more and more aquatic shops catering for the needs of shrimp keepers. Nowadays you can find a whole range of specialist soils, decoration and equipment tailored to them. Their popularity isn’t surprising. They’re adaptable, relatively easy to keep and breed, colourful and perfect candidates for nano tanks, bringing the aquatic world close to even those with only limited space available. 

The availability of stock is astounding. There are the bulletproof species (like Cherry shrimp, Neocaridina) for absolute beginners and more challenging ones (like the Crystal Red shrimp and Taiwan Bees, Caridina cantonensis) for more advanced keepers. But what if the colourful palette of the Cherry Shrimp varieties or the intricate patterns of the various TaiTibees don’t satisfy your needs or you want new challenges? Well, that’s when the shrimp species from Sulawesi (formerly Celebes) enter the picture.

Sulawesi selection

Seasoned aquarists are likely familiar with the name of Celebes and will know the fantastic fish hailing from this Indonesian island — species such as Celebes Rainbow, Marosetherina ladigesi, and Celebes Halfbeak, Nomorhamphus liemi, just
to name a couple. 

Sulawesi also has its share of lesser-known secrets: the deep ancient lakes hiding among the highlands of the island. Lake Poso and the Malili Lakes (consisting of five smaller lakes – Towuti, Matano, Mahalona, Masapi, Lontoa) each have a very specific fauna including
a variety of gastropods and crustaceans that you can’t find anywhere else in the world. 

Due to the position of the lakes, only small amounts of organic matter get into them, and their inhabitants had to adapt to the oligotrophic environment. Food can be scant in these lakes. Being mainly diatom, detritus and algae eaters feeding Sulawesi shrimps can cause some problems, something I’ll return to.

Within the lakes there are niche habitats with their unique fauna.

You will find bare sandy bottoms, leaf-and-wood littered areas, macrophyte zones as well as hard rock territories. Certain shrimp species can only be found in one particular microhabitat, while others have a wide distribution across several zones.

What all common in every area is the water temperature. It’s over 27°C near to the surface and similarly 27°C even close to the bottom of the often extremely deep (590m) lakes. This means that the Sulawesi shrimps and snails require much higher than the usual temperatures. 

Water chemistry-wise these lakes have curious parameters. They’re relatively soft (4-8°GH, 3-5°KH), yet quite alkaline at 8.5pH, diverging from the usual ‘soft and acidic’ or ‘hard and alkaline’ trends. It’s the carbonate and bicarbonate content that regulate acidity, so creating and maintaining a proper Sulawesi environment with low carbonate hardness could be challenging. 

Those who have never seen a Sulawesi shrimp may ask, if there are so many difficulties then why bother? My answer is simple: they’re special and bring colours that you only usually see among marine species. 

Sulawesi shrimps all belong to the Caridina genus, like many of our favourite species, such as the Amano shrimp, Caridina multidentata. However, unlike this species the Sulawesi species are fully adapted to a freshwater environment, so they produce well-developed offspring that don’t require saltwater to survive. This possibility of home-breeding just adds to the appeal of these little eye-catchers.

A cold start

Having kept and bred ‘ordinary’ shrimp species for over a decade I decided to take the plunge and dive into the world of Sulawesi. I set up a tank for a small group of Cardinal shrimp, Caridina dennerli, and then — despite of my best efforts — all but one of them died within a week. The one remaining shrimp was a female carrying eggs, so I hoped the best. Unfortunately, out of the around 12 eggs only two hatched, but even those disappeared within a week. The female lasted for a few months. 

After this failure I reviewed the potential reasons. The first mistake I committed was to get the shrimp during the winter months. When they arrived, the water they were in was below 20°C despite the presence of a heat pack. That’s way too low for such a warmth-lover, and it’s possible that even that brief chill can cause severe harm. Discussing my experience with other Sulawesi shrimp keepers they concurred, many of them reporting similar issues. Cooling down seems to affect wild-caught specimens to a greater extent, and the stress of being caught and then transported to the other side of the world weakens their immune system more. Add a few days starvation prior to and during transit and you can see why they arrive in poor condition.

Read the rest of the feature in the April issue, available to read instantly on our digital edition HERE  or purchase the print edition HERE
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