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Fiddler Crab Tank Mates – The 8 Other Species Your Tank Needs Today

A fiddler crab holding up its claws guarding his heap of mud. Also known as calling crab. (urca)

 Fiddler Crab (Urca) Brief Overview

Uca vocans, Fiddler Crab walking in mangrove forest at Phuket beach, Thailand

  • Care Level: Easy
  • Temperament: Peaceful
  • Size: 2-3 Inches
  • Fiddler Crab Diet: Omnivore

The Fiddler Crab (genus: Urca), aka calling crab, is a semi-terrestrial marine crab belonging to the Ocypodidae family composed of small crabs living along sea beaches or the brackish inter-tidal mudflats, swamps, and lagoons. Nevertheless, they could also live in your aquarium. But what are some good Fiddler Crab tank mates? This post will cover the best ones, along with additional information.

The Fiddler Crab we’re featuring today is a peaceful little fella’, easy to take care of, and quite good at getting along with his tank mates. He has both gills and a kind of primitive lung, which allow him to breathe both in water and on the ground.

One interesting aspect of Fiddler crabs is their claws and how they appear to be waving at each other. This behavior is present when they’re courting their females or fighting with other males for territory. Don’t worry; the only time they’ll show aggressive behavior is when they compete with other males.

Every eight weeks, you’ll observe their exoskeleton thrown coming off. They molt in this time, and if they had lost a limb, another one would develop by the time they molt. Don’t worry.

You can tell a fiddler crab male from a female based on their claws. The males have one big claw they use as a tool and a second smaller one. The females have only two small claws.

At the rear of their claws, you’ll observe 4 pairs of legs they use to walk around. The fiddler crab’s body is covered in a hard shell to protect their main organs against enemies.

As for color, they are not as brightly-colored as fish. They are generally brown or orange all over.

Since the fiddler crabs love brackish water, it might prove a challenge to pair them with most freshwater fish. However, there are always solutions, and this is what we’re going to discuss here.

Let’s see what the best 8 fiddler crab tank mates are! Note that they’re in no particular order.

The Molly Fish (Poecilia sphenops)

Colorful aquarium Molly fishes. They inhabit fresh water streams and coastal brackish and marine waters of Mexico. The wild-type fishes are dull, silvery in color.

  • Care Level: Easy
  • Temperament: Peaceful
  • Size: Up to 4.5 Inches
  • Molly Fish Diet: Omnivore

Molly Fish Appearance

The Mollies as they’re commonly named among enthusiasts, present a flattened, colorful body. There are a lot of Molly types out there that you can choose from. They’re very adorable, especially with that dorsal fin raised as a fan.

You can tell a female Molly from a male one by their size, with females being slightly larger and boasting an anal fin that spreads into a fan, compared to a male’s pointy fin.

You will also be able to notice a pregnant female since they’re so much larger than the other females in the aquarium.

Molly Fish Temperament and Behavior

The Mollies are very peaceful, but they do not like being crowded with too many fish. They could get aggressive towards other aggressive tank mates.

To keep them together with fiddler crabs, you’ll need a 30-gallon tank. They are very active and seem happy to interact with their tank mates all the time. They like schooling together.

Why Molly Fish Are Good Tank Mates

Mollies like low-salinity environments, so they could thrive with fiddler crabs. Moreover, they’re fast-swimmers, highly energetic, and could get away from the crab’s claws with no problem.

However, keep in mind that these fish will require a lot more water, so make sure you choose a big enough tank for pairing fiddler crabs and Mollies together.

The Platy Fish (Xiphophorus maculatus)

Wagtail Platy Fish, xiphophorus maculatus

  • Care Level: Beginner
  • Temperament: Peaceful
  • Size: 3 Inches
  • Platy Fish Diet: Omnivore

Platy Fish Appearance

The Platies are really adorable small fish, boasting a high resilience to any sort of disease. They’re very colorful, tiny, and present a laterally-flattened body. Their fins are short, and the tail looks like a little royal fan.

There are many variations and hybrids on the market right now, and that’s why their colors vary a lot. Some of the most popular Platies are red, blue, yellow, green, and white.

Usually, you can tell their appearance by their different names. For example, you’ve got Blue Mirror Platy and Bleeding-Heart Platy. Then there’s the Coral Platy, the Salt and Pepper Platy, or the Yellowtail Platy.

Platy Fish Temperament and Behavior

The Platy fish love to spend their time in small groups. They’re vivacious fish and would breed easily.

Their favorite place is usually the middle of the aquarium, where they could also hide between the floating leaves and plants. They do not display aggressiveness but make sure you keep the female-male ratio to 1:1. Also, keep the aquarium covered since they can jump out of it. Yes, they can!

Why Platies Are Good Tank Mates

Platy fish are very peaceful and very active. They can swim around fast and would easily escape a fiddler crab’s claws. If they get aggressive, that’s usually amongst themselves, namely among the males.

They get along well with other peaceful and small fish or invertebrates, as well. That’s why they’re good fiddler crab tank mates.

The Swordtail (Xiphophorus hellerii)

Swordtail

  • Care Level: Easy
  • Temperament: Peaceful
  • Size: 6.5 Inches
  • Swordtail Diet: Omnivore

Swordtail Appearance

The swordtail is known for having a long fin on their tail that looks like a sword. It’s long compared to their body length. Only the males have it, so yes, you can tell them apart very easily.

In the wild, the swordtail is olive green, with a distinguishable red lateral stripe running along the full length of their body.

However, in captivity, due to extensive breeding, you can find a lot more varieties, from red to orange and even black swordtails.

They will get more vividly-colored if they love their environment and are not stressed at all.

Swordtail Temperament and Behavior

They love spending their time in the community with other small and peaceful fish. Although they live in groups, they’re not the shoaling type.

Swordtails are peaceful and don’t like any boisterous species. If they sense the slightest threat, they’ll hide behind the plants and tank decorations.

They usually swim in the aquarium’s middle and upper levels and rarely go down to the bottom. If you give them a big aquarium with enough space, they will swim around very fast for you to enjoy.

Why Swordtails Are Good Tank Mates

These lively, small, adorable beings enjoy the company of other peaceful and passive tank mates. You can mix them with Fiddler Crabs without a problem, as they rarely venture to the bottom of the aquarium and are fast, peaceful swimmers.

The Guppy (Poecilia reticulata)

Guppy

  • Care Level: Easy
  • Temperament: Peaceful
  • Size: 0.6 – 2.4 Inches
  • Guppy Fish Diet: Omnivore

Guppy Fish Appearance

Guppies are some rare beauties of the aquarium world. In the wild, they’re usually just grey, with some colorful stripes and spots on their tails.

However, thanks to the love they’ve received from enthusiastic breeders, these days you will find many more Guppy varieties with a lot of bright, vivid colors and patterns, and splashes all over their body and tail. It’s quite hard to describe that. You’ll have to see it for yourselves.

Males and females are quite different, with the females being considerably larger than their male counterparts.

Guppy Fish Temperament and Behavior

Guppies like two things: peace and society. They like to swim around a lot and impress their females with their colorful fins.

When they feel threatened, they’ll be timid and hide.

Why Guppy Fish Are Good Tank Mates

First thing first, they’ll add a few splashes of color to your fiddler crab aquarium. They are peaceful and can be kept with other peaceful communities, and also get along well with a large variety of non-fish animals, such as Ghost Shrimp, or African Dwarf Frogs.

So, yes, they’re some really good fiddler crab tank mates.

The Bumblebee Goby (Brachygobius xanthozona)

Bumblebee Goby, hypogymnogobius xanthozona

  • Care Level: Moderate
  • Temperament: Peaceful
  • Size: Up to 1.5 Inches
  • Bumblebee Goby Diet: Carnivore

Bumblebee Goby Appearance

The Bumblebee Goby looks like a bumblebee, yes, you’ve guessed that right. They present some yellow or orange patterns on their side. Their bodies are slender, with a small head. Females tend to be a bit bulkier than males.

By taking a second look at those adorable round, protuberant eyes, you might fall in them now and forever.

Bumblebee Goby Temperament and Behavior

The Bumblebee Gobies might be shy at first, but once they get used to their new environment and if nothing stresses them out, you’ll see them swimming around in no time.

They are quite curious and playful if they feel safe. Although males might provoke some territorial squabbles from time to time, they are an overall peaceful species.

Why Bumblebee Gobies Are Good Tank Mates

Bumblebee Gobies love brackish waters, so do Fiddler Crabs, so they’ll both be happy in their new environment.

Bumblebee Gobies are not much bigger than fiddler crabs, so they won’t see them as food, and they love swimming and playing around swiftly, so they won’t interfere much with the bottom dwellers.

The Nerite Snail (Neritina natalensis)

Zebra Nerite Snail in a Tank
Zebra Nerite Snail. Photo Credit: Evan Baldonado
  • Care Level: Easy
  • Temperament: Peaceful
  • Size: Up to 1 inch
  • Nerite Snail Diet: Herbivore

Nerite Snail Appearance

There are a couple of variations of Nerite snails. All of them have a hard, coiled shell and muscular feet to move around.

The zebra and tiger Nerite Snails have black and yellow stripes that go around their shells pointing towards the coil’s center. The tigers’ stripes are a little more jagged than the Zebras’ and have a more intense orange color.

There are also the Oliver nerite snails and the hornet nerite snails. The first ones are the most common you will find in aquariums. The hornet nerite snails also present a series of dark “horns” on their shells.

Nerite Snail Temperament and Behavior

Nerite Snails not very active, and they’re peaceful. They eat the algae in the aquarium and won’t bother any other fish. They also sleep in 2-3 cycles per day.

Why Nerite Snails Are Good Tank Mates

They’re peaceful creatures that like to stay out of the way of the Fiddler Crabs. They love brackish waters as well and would keep the aquarium clean.

However, the risk of crabs hunting them down is still present. Pair them with care and follow their behavior and progress at first.

The Amano Shrimp (Caridina multidentata)

Amano shrimp named after the famous Japanese aquarist Takashi Amano

  • Care Level: Easy
  • Temperament: Peaceful
  • Size: Up to 2 inches
  • Amano Shrimp Diet: Omnivore

Amano Shrimp Appearance

Commonly known as Yamato Shrimp, or Japanese shrimp, these small creatures are native to Japan and Taiwan and can be easily recognized thanks to their translucent body, with a hint of grey.

They present a series of dots in the shades of blue or red, running along their bodies. Interestingly, these dots will help you tell a male from a female and give you hints regarding their diet.

An Amano Shrimp that predominantly feed on algae will have greener shade to its dots.

Amano Shrimp Temperament and Behavior

In general, Amano Shrimp do not cause any trouble to anyone. Nevertheless, they are fierce if they need to fight for food.

They like heavily-planted aquariums for when they molt, they’ll feel at their most vulnerable and will need to hide away from anybody.

Why Amano Shrimp Are Good Tank Mates

They’re one choice if you want to pair your favorite fiddler crabs with invertebrates. They are peaceful and won’t bother the Fiddler Crabs. They’re pretty much the same size as the crabs, so, with a little luck, they’ll stay out of each other’s way.

The Ghost Shrimp (Palaemonetes)

ghost shrimp

  • Care Level: Easy
  • Temperament: Peaceful
  • Size: 1.5 Inches
  • Ghost Shrimp Diet: Omnivore

Ghost Shrimp Appearance

They look like ghosts, yes. They have a translucent body to help them evade their predators. This makes them interesting creatures, as you can observe the inner workings in the body, like when they process food.

The females will grow larger than males, and they both display a certain kind of colored dots on their backs. They present two antennas they use to get tactile and chemical information from their environment.

The softest part of their bodies is covered in a hard protective shell for self-defense against predators.

Ghost Shrimp Temperament and Behavior

The ghost shrimps are good for clearing the aquarium and keeping the algae levels down. They will be the absolute professional cleaners of the aquarium. This is their main activity, which will keep them busy all day long. They’re highly active in their endeavor.

Why Ghost Shrimps Are Good Tank Mates

They’re gentle creatures and quite small, so they could be prey for most large tank mates. Luckily, the fiddler crab is not much bigger and with a little luck, they’ll leave the ghost shrimps alone.

Fiddler Crab Tank Mates Summary

The best fiddler crab tank mates are peaceful fish or invertebrates that are not too large or too small and could swim swiftly and keep away from the fiddler crab’s rapacious claws.

Furthermore, the tank mates that share the same affinity for brackish waters, like Bumblebee Gobies or Nerite Snails are good ideas, for they’ll thrive in their natural kind of environment.

In the end, if you follow the no. 1 rule of thumb: nothing too large that could fit a fiddler crab through their jaws, and if you also obey the no. 2 rule: tank mates that share the same temperament, you’re on the right track.

Now, the only challenge is the environment and the fact that fiddler crabs love brackish waters above all, but as you could see, there are solutions, and you can do this.