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What is a Spiny Eel?

Erica Stratton
Erica Stratton

A spiny eel is not actually a member of the eel family—it is a type of fish. There are two different species of fish that have this nickname. One type lives in freshwater, while the other is a saltwater fish. Both of them have long, thin, eel-like bodies, but unlike true eels, they have three distinct spines on their dorsal fins.

The saltwater eel is from the family Notacanthidae. It swims close to the sea floor. It feeds on bottom-dwelling animals such as anemones and worms, which burrow in the mud. The marine spiny eel is further divided into 11 more species. Each of these fish are characterized by different fin-to body ratios, numbers of spines, and jaw shapes. Some have narrow jaws, while others have ones which are blunt, wide, and toothy.

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The freshwater spiny eel is of the family Mastacembelidae, which includes swamp eels. It is characterized by its long, ribbon-like body and its needlelike snout. This type of spiny eel is known as an aquarium fish. Several species have beautiful coloring. The peacock eel in particular is prized for its green and blue coloring.

In the wild, these freshwater fish tend to live in swamps and brackish water, feeding off of worms and other tiny animals. For this reason, their aquariums will need to be furnished with plants or rocks where the eel can hide during the day. Being a nocturnal species, the eel will then come out in the evening for feeding.

The spiny eel will not eat pellets or flakes if kept in captivity. Its food needs to be alive and moving in order for it to take an interest. Most often, owners will feed their eels bloodworm, larvae, or tiny crustaceans. A spiny eel is also more sociable than most fish in that it is not shy about approaching people for food and will eat out of someone's hand when it is placed in the tank.

When in an aquarium, spiny eels do not often spawn. This may be due to difficulties the fish have mating rather than any kind of inherent impossibility. There are few resources for those looking to breed the fish, and some guides to keeping them in aquariums will identify them incorrectly. It can also be difficult to transition the fast-moving eels to a separate aquarium where the spawning can take place. If they are in a tank with other fish, their eggs may be eaten before they can hatch.

Frequently Asked Questions

What exactly is a spiny eel?

A spiny eel is a freshwater fish that belongs to the order Synbranchiformes, which is known for its elongated body and spine-like fin rays. Despite their name, spiny eels are not true eels but have a similar appearance due to convergent evolution. They are popular in the aquarium trade for their unique look and behaviors.

Where can spiny eels be found in the wild?

Spiny eels are native to tropical and subtropical regions of Africa, South America, and parts of Asia. They inhabit slow-moving waters such as swamps, creeks, and rivers where they can burrow into the substrate. Their distribution in these areas allows them to thrive in environments with low oxygen levels.

What do spiny eels eat?

Spiny eels are carnivorous, feeding primarily on small invertebrates like worms, crustaceans, and insect larvae. In the aquarium setting, they may also accept frozen or live foods such as bloodworms and brine shrimp. Their diet reflects their predatory nature and adaptation to hunting in soft substrates.

How do spiny eels reproduce?

Reproduction in spiny eels is not well-documented, but it is known that they are egg layers. In the wild, they likely spawn during the rainy season when water levels rise. The eggs are adhesive and are deposited on plants or other submerged surfaces. Parental care is not common among spiny eels.

Are spiny eels easy to keep in home aquariums?

Spiny eels can be a challenge to keep in home aquariums due to their specific needs. They require a soft substrate for burrowing, ample hiding places, and a diet of live or frozen foods. They are also known for their escape abilities, so a tightly fitting lid is essential. Proper care and a well-maintained environment are crucial for their well-being.

What is the lifespan of a spiny eel?

The lifespan of a spiny eel can vary depending on the species and conditions in which it is kept. In a well-maintained aquarium, spiny eels can live for several years, with some species reportedly living up to 10 years. Their longevity is a testament to their adaptability and resilience in diverse environments.

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