How Long Do Emerald Crabs Live? Emerald Crabs’ Life Span

Emerald Crabs are well known for preventing algae growth in reef tanks, so you’ve probably heard of them. Like other species of the earth, emerald crabs have to die. But before you put them in your tank, you should know how long emerald crabs live.

The average lifespan of emerald crabs can be between two and four years. Emerald crabs do not live for very long, and their deaths can be heart-breaking. If you have a few emerald crabs in your aquarium, you’ve probably seen them die between two and four years. Let’s check out the lifespan of emerald crabs.

What Is the Life Span of Emerald Crab?

Usually, an emerald crab can live for two to four years, especially in the ocean. The lifespan of emerald crabs in the reef tank can vary because of how you maintain them.

The lifespan of emerald crabs also depends on how you care for them. If emerald crabs don’t get enough food, they will get weaker and eventually die. The average lifespan of emerald crabs is between two and four years. However, some crabs have a five-year lifespan. From crab to crab, the life span can differ.

It might only live for a short time if the salt level in the reef tank is low, or the water is dirty. So, it is vital to know how to care for emerald crabs in aquariums to keep them alive.

How Do Emerald Crabs Reproduce?

Emerald crabs mate similarly to other kinds of crabs. They are social animals, so they need a partner in order to reproduce. Mating usually occurs at night or during the early morning hours. During this time, male and female emerald crabs will come together in pairs and mate. For mating, the male crab will climb atop the female crab.

Instead of laying eggs, females carry them in a pouch under their bellies. Baby crabs are released from the pouch by climbing to a high perch and opening the pouch. Little microbes and other types of algae provide nourishment for new-born crabs. The female will usually stick close by until the young are old enough to scavenge on their own.

See also  Hoff Crab (Kiwa tyleri) - Habitat, Anatomy, Diet And Other Facts

How to Take Care of Emerald Crabs in An Aquarium?

Emerald crabs do not need a specific diet or environment. But if you are keeping them in an aquarium, you need to feed them properly and maintain their environment. The environment of an aquarium is different than that of the ocean, which means emerald crabs require proper maintenance.

However, these maintenance tasks are not as hard as you think. Here are some simple tips to keep an emerald crab alive in an aquarium:

Keep The Tank Size Big Enough

You need a tank size that can hold at least 20 to 30 gallons of water to keep emerald crabs. Emerald crabs can still live in a small tank, but they can be very aggressive because they don’t have enough space to thrive.

To keep emerald crabs alive, they need to swim peacefully and thrive. A small tank will suffocate them, and they will die eventually.

Food And Habit

Emerald crabs love eating algae, such as hair and bubble algae. Most people bring them only to clean the algae and meaty scraps from the aquarium.

However, you also need food supplements and other foods to feed emerald crabs. You can feed them chopped shrimp, dried nori, dried seaweeds, etc., to keep emerald crabs alive. Make sure to hand-feed them because they tend to hide under the rocks.

Water Parameters

Despite the fact that emerald crabs can live in a reef tank with all of the configurations, you must still maintain certain water quality standards. Since crabs naturally live in shallow waters, warm waters are ideal for them. Additionally, the pH of the water should be more alkaline for them.

Emerald Crab

Keep the water between 72 and 82 degrees Fahrenheit; it is best if it is above 75. The ideal pH range for emerald crabs is 8.0 to 8.4. The water hardness has to be 8 to 12 dKH, which is perfect for emerald crabs to thrive. Keep the Specific Gravity within the range of 1.020 to 1.025 (1.023 is ideal).

See also  Barnacles On Crab: Do Barnacles Hurt Crabs?

Things To Put in The Reef Tank to Keep Emerald Crabs Live

When you are putting emerald crabs in a reef tank, make sure to keep certain things around to make the crabs comfortable. Emerald crabs love to stay under rocks. You need live rocks and corals for emerald crabs in the reef tank.

Make sure to create a natural environment for emerald crabs in the reef tank. Keep rocks covered with algae so that crabs can eat them. Hair algae with rocks would be best for emerald crabs. They also roam around at night, so make sure to keep the lighting natural.

Artificial light might cause disturbances for emerald crabs because they roam around at night. The crabs will be uncomfortable if the light is left on 24 hours a day.

What Is the Behavior of Emerald Crabs?

Emerald crabs are characterized as being calm and secure with their tankmates in some manuals and care sheets. However, people also reported that emerald crabs had attacked their tankmates before.

When other green crabs invade their territory, they might become aggressive. If emerald crabs are hungry and they can’t find any algae or leftover meat to consume, they will attack other fish and eat them.

Remember that fish, snails, and other crabs can become aggressive in certain circumstances if you have any of those animals. If the tank mates are not properly selected, it is possible that danger will materialize.

Even though they have the potential to be violent, emerald crabs are fascinating to watch. These organisms initially live mostly at night, as was already mentioned.

Can You Keep Two Emerald Crabs Together?

Well, emerald crabs are aggressive in nature. Even if they are both emerald crabs, it is still possible that they can attack each other. You should keep two crabs separate in separate tanks or at least give them enough space in the same tank so that they won’t fight.

See also  What Do Emerald Crabs Eat? Emerald Crab Eating Habit

If you want to keep two emerald crabs together, make sure to give them plenty of algae and food sources so that they don’t compete for resources. You also need to provide hiding spots so that the crabs can retreat from each other if necessary.


Are emerald crabs easy to keep?

Emerald crabs are easy to maintain, but they need a specific environment to live in. You need a lot of live rocks and corals if you are getting emerald crabs for an aquarium or reef tank.

It is because emerald crabs need live rocks to hide under them. They are nocturnal, meaning they only roam around at night and hide under rocks during the day. But feeding emerald crabs is easy because they are omnivores and scavengers. This means they eat meat and plants and leftover meaty fish and algae.

Are emerald crabs freshwater crabs?

Emerald crabs are not freshwater crabs. This means you cannot keep emerald crabs in a freshwater aquarium. You need saltwater to keep emerald crabs alive. You can put emerald crabs in a saltwater reef tank, and they will thrive.

Can emerald crabs have babies?

Like other crustaceans, emerald crabs can have babies. Female emerald crabs usually do not lay eggs. Female emerald crabs carry their eggs in a pouch that is located under their belly. They ascend to the highest point and release their babies when it is time to give birth.

What are emerald crabs good for?

Emerald crabs balance the ecosystems of your reef tank and the ocean. They eat leftover scraps to keep the reef tank or aquarium clean and hygienic.


To maintain them properly, it is vital to know how long emerald crabs live. If you are one of those people who don’t know how to take care of emerald crabs, then I’m sure this blog has helped you.

Emerald crabs are very special to our ecosystem. To maintain the balance of the ecosystem, we must keep them alive and prevent their extinction.

Leave a Comment