Sawagani Crab Pet Care: Tank Setup, Water Quality & Feeding Tips

Small but interesting, the Sawagani crab pet is a good choice for freshwater aquariums. Unlike other common aquarium pets, such as Thai micro crabs, the Sawagani crab requires a stable environment with clean water, good filtration, and nutrient-rich food. 

Whether you’re a beginner or an experienced aquarist, learning about their care requirements, ideal conditions in the tank, and proper nutrition will go a long way in raising a healthy, stress-free pet.

 In this guide, I’ll cover everything you need to know about keeping Sawagani crabs as a pet, from their tank requirements to feeding habits, so that your aquatic companion can thrive.

What is a Sawagani Crab Pet?

The Sawagani crab (Geothelphusa dehaani) is a small freshwater crab native to Japan and is commonly found in clean mountain streams and rivers. This species is known for its compact size, semi-aquatic lifestyle, and adaptability, making it a popular choice for aquarium enthusiasts. 

Unlike most aquatic crabs, such as vampire crabs, the pet sawagani crab requires access to both land and water to stay healthy. With their hardy nature and unique behaviors, many people keep Sawagani crabs as pets, requiring a well-maintained habitat with stable water parameters and proper nutrition to stay healthy.

A Quick Overview of Sawagani Crab Facts

  • Common Names: Sawagani Crab, Japanese River Crab 
  • Scientific Name: Geothelphusa dehaani 
  • Care Level: Moderate 
  • Temperature: 68–82°F (20–28°C) 
  • Temperament: Semi-territorial 
  • Color: Light brown, reddish-brown, or pale orange 
  • Size: 1.5-2 inches 
  • Diet: Omnivore
  • Aquarium Type: Freshwater with land access 
  • Sleeping Nature: Nocturnal
  • Lifespan: 5 to 10 years

Where Do Sawagani Crabs Come From?

Sawagani crab pet
Image source: Orbis-pictus.jp

The Sawagani crab originates from Japan and can usually be found in cool, fast-flowing mountain streams and rivers. Some crabs, like horseshoe crabs or pea crabs, would want a marine environment, while sawagani crabs live in freshwater. These small crustaceans are adapted to living in an area with clean, oxygen-rich water.

Are Sawagani Crabs Fully Aquatic?

No, Sawagani crabs are not fully aquatic. Land crab pets live almost their entire life on land and freshwater pom-pom crabs spend their whole life submerged; sawagani crabs need a habitat containing both water and land. They will molt and hide from predators in damp, rocky areas near streams. 

Note: If you are going to keep sawagani crabs as pets, be sure to set up your tank with both aquatic and terrestrial zones to replicate their natural environment.

How Big Are Sawagani Crabs?

Sawagani crabs generally reach a size of about 1.5-2 inches. Despite their small size, they are active and quite curious, thus interesting for aquarists to keep.

Sawagani Crab Pet Growth and Molting

Like all crabs, Sawagani grows by periodically molting their old exoskeleton to develop a larger one. Younger crabs molt every few weeks, while older ones may only molt a few times a year. A diet rich in calcium and good conditions of the water will help ensure healthy growth and a strong shell.

What Do Sawagani Crabs Eat?

Sawagani crab pets are omnivorous scavengers, and they can eat a mix of plant and animal matter. In the wild, their diet includes:

  • Algae and biofilm
  • Small invertebrates
  • Decaying plant matter
  • Detritus 

In captivity, they have proved very hardy while having a varied diet that includes commercial crab food, blanched vegetables, protein sources like bloodworms, and calcium supplements for good, healthy shell growth.

How Long Do Sawagani Crabs Live?

There is limited documented data on the exact lifespan of Sawagani crabs in captivity. However, like similar freshwater crabs, they usually live 5-10 years with proper care.

how to keep a pea crab alive
Image source: Orbis-pictus.jp

Their lifespan can be prolonged with:

✔ Stable water parameters

✔ A well-maintained, partially aquatic tank setup

✔ A healthy, calcium-rich diet

Unique Behaviors of Sawagani Crabs Pet

Sawagani crabs have several fascinating behaviors, making them fun to observe. 

  • Digging and hiding: They usually burrow into the substrate or lie concealed under the rocks.
  • Nocturnal activity: Most of them are active in the night, like many crabs, when they forage and explore after the lights go out.

Tank Mates and Compatibility

Generally, Sawagani crabs are quite docile and non-aggressive but may be territorial with other crabs. They do best if housed alone or in a carefully planned community tank with species that won’t outcompete them for food. Avoid aggressive fish or fully aquatic crabs like Vampire crabs or Panther crabs, which may not tolerate them well.

Set Up the Right Habitat for a Sawagani Crab Pet

Sawagani crabs are semi-aquatic, meaning they require both aquatic and terrestrial areas in their enclosure. Herein is how to set up the perfect habitat for them: 

Selection of the Right Tank 

  • Tank Size: The ideal tank size for a small group of Sawagani crabs is 10 gallons. 
  • Tank Type: A glass or acrylic aquarium with a tightly fitting lid to prevent escape.
  • Water-to-Land Ratio: Strive for 60% water and 40% land to simulate their natural environment.

Note: Create a low-water arrangement with sloped land areas for easy movement by your crab from water to land.

Water Needs

  • Type: Dechlorinated freshwater or spring water. Never use tap water containing chlorine.
  • Filtration: A soft sponge filter would work best to keep the water clean without creating hard currents.
  • Temperature: Maintain a temperature of 68–82°F (20–28°C).
  • pH: The pH should be between 6.5 and 7.5 to make it like their natural environment.

Land Area & Substrate

  • Land Area: Use smooth rocks, driftwood, or a sandbank to create a sloping area of the land.
  • Substrate: A mix of fine sand and coconut fibre maintains the humidity and allows burrowing.
  • Hiding Places: Add caves, logs, or leaf litter to provide security and enrichment.

Can You Own a Crab as a Pet?

Of course, it can be quite fascinating and fun to have a pet crab with the Sawagani crab, land crab, and even a horseshoe crab. Each species requires different kinds of attention, and with the right setup, crabs can make low-maintenance and fascinating pets.

What’s it Like to Own a Pet Crab?

Crabs are not your typical cuddly pet, but they have amazing personalities. They are active, love to explore, and even show recognition towards their owners over time. It’s quite entertaining to watch them climb, dig, and hunt for food! 

I love seeing my crabs molt and grow; it’s always exciting to see them come out of their old shell bigger and stronger. Compared to fish or reptiles, they are also less maintenance, given that you are giving them the right habitat.

Here is a video where a sawagani crab is kept as a pet:

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