Fiddler Crabs Tank Setup and Care Guide: Everything You Need to Know

Fiddler crabs are fascinating, easy-to-care-for creatures that can make great additions to a home aquarium or paludarium. Males have a distinctive large claw which looks slightly like a fiddle. Females, on the other hand, have two similar size claws.

Let’s take a closer look at how to care for these fascinating creatures.

Key Takeaways

• Fiddler crabs require both land and water areas in their tank. A paludarium with a sloping substrate that allows for both a shallow water area and a dry land area is ideal.
• They need a minimum tank size of 10 gallons for three to four crabs. They prefer shallow water and a large surface area. A long or wide tank is better than a tall or narrow one.
• Fiddler crabs require brackish water with a specific gravity between 1.005 and 1.08, a pH level between 8.0 and 8.3, and water hardness between 12 and 30 KH. 
• They eat various foods, including sinking pellets, frozen or live brine shrimp, bloodworms, vegetables, and even small pieces of meat. Feed them once or twice a day, providing only as much food as they can eat in a few minutes.
• Fiddler crabs are social animals and should be kept in groups of at least three. They’re active during the day and will spend most of their time digging burrows and scavenging for food. 
• They shed their exoskeletons periodically as they grow. During this time, they are vulnerable to attack, and it is best to provide hiding spots for them to rest. After molting, they will consume their old exoskeleton to regain the nutrients lost during the process.
• Fiddler crabs can be kept with certain fish species that are compatible with their tank requirements, such as platies, swordtails and bumblebee gobies.

Scientific Taxonomy

There are over 100 species of fiddler crabs around the world, and they all share the following taxonomy:

• Kingdom: Animalia
• Phylum: Arthropoda
• Subphylum: Crustacea
• Class: Malacostraca
• Order: Decapoda
• Suborder: Pleocyemata
• Infraorder: Brachyura
• Superfamily: Ocypodoidea
• Family: Ocypodidae

Which Tank Setup is Best For Fiddler Crabs?

When setting up a tank for fiddler crabs, it is important to consider their natural habitat. Fiddler crabs require a paludarium (an aquarium that combines both terrestrial and aquatic elements) with a sloping substrate that allows for both a shallow water area and a dry land.

Tank Size

Fiddler crabs are social creatures best kept in groups of at least three. This means you need a minimum tank size of 10 gallons, but larger tanks are better and provide more space for the crabs to move around and explore.
Fiddler crabs like shallow water and a large surface area. A long or wide tank is better than a tall or narrow one. 

Substrate

Fiddler crabs require a moist, sandy substrate. Sand is the best choice as it allows the crabs to burrow and maintains good moisture for molting. 

A substrate depth of at least 2 inches is recommended to accommodate the crabs’ digging habits. Keep the substrate moist, but not waterlogged.

Decorations

Fiddler crabs enjoy having things to hide under and climb over, like rocks, caves, and small plants. However, ensure that the decorations don’t take up too much space and that there’s plenty of room for the crabs to move around.

Filter

A filter is necessary to keep the water clean and prevent the buildup of harmful toxins. A hang-on-back filter is a good option for a fiddler crab tank as it provides adequate filtration without taking up too much space. It is also important to clean the filter regularly to ensure that it is functioning properly.

Water Parameters

Try to maintain fiddler crab aquariums in the following ranges:

• Brackish water with a specific gravity between 1.005 and 1.08
• A pH level between 8.0 and 8.3
• Water hardness between 12 and 30 KH

A standard test kit and hygrometer will help you monitor and adjust these parameters. Change the water in the tank regularly to remove waste and prevent the buildup of harmful chemicals. I’d recommend a 25-50% partial water change once a week.

Temperature and Humidity

Maintain the temperature in a fiddler crab tank at 75-85°F (24-29°C) and keep the humidity high by using a heater and a humidifier.

How Do I Care For A Fiddler Crab?

Fiddler crabs require specific care to thrive in captivity. In this section, we will explore the feeding, behavior, health, common diseases, and molting of fiddler crabs.

Feeding

In the wild, fiddler crabs feed on algae, detritus, and small invertebrates. In captivity, they can be fed a diet of sinking pellets, frozen or live brine shrimp, bloodworms, and vegetables such as spinach or zucchini and even small pieces of meat.

It is essential to ensure that the food is small enough for them to eat and that it sinks to the bottom of the tank. Feed your fiddler crabs once or twice a day, providing only as much food as they can eat in a few minutes.

Behavior

Fiddler crabs are social animals, and it is best to keep them in groups of three to five. They are active during the day and will spend most of their time digging burrows and scavenging for food. The males will also wave their large claws to attract mates or intimidate other males.

Fiddler crabs are great climbers and swimmers, and they can easily escape from their aquariums.

To prevent this, use a tank with a low water level and ensure that plants and decorations don’t provide easy access to the top of the tank.

Health

Fiddler crabs are generally hardy creatures, but they can still fall ill. A happy and healthy fiddler crab will be active and display normal behavior, such as feeding and burrowing. If you notice any changes in behavior or appearance, it may be a sign that something is wrong.

Common health issues to look out for include shell rot, which can occur if water quality in the tank is poor, and mites, which can infest the gills of the crab.

Fiddler crabs can also suffer from bacterial infections, fungal infections, and parasites. These can all be avoided through proper care and by carefully monitoring water conditions. 

Molting

Fiddler crabs shed their exoskeletons periodically as they grow. During this time, they are vulnerable to attack, and it is best to provide hiding spots for them to rest. After molting, they will consume their old exoskeleton to regain the nutrients lost during the process.

What Can I Keep With My Fiddler Crab?

When it comes to choosing tank mates for your fiddler crabs, it’s important to select peaceful and fast-moving species that can coexist well with the crabs and stay out of reach of their claws.

Some of the best fish to keep with fiddler crabs include:

• Platies
• Swordtails
• Bumblebee gobies

It’s important to make sure there is plenty of water for the fish to swim in and that they are not too large for the tank.

Summary

Fiddler crabs can make great additions to a home aquarium or paludarium as long as you meet their care needs.

As long as you clean regularly, monitor water conditions, and feed them on a good schedule, you’ll love your new crabs.

If you liked this article, you might find intersting our articles about Panther crabs, Thai micro crabs , Vampire crabs, and Red claw crabs.