
Is an Eel a Fish or a Snake? Here’s the Scientific Explanation
Fundacion Rapala – At first glance, it’s easy to confuse an eel with a snake. Their elongated, slimy bodies and slithering movements often blur the lines between aquatic and reptilian life. However, scientifically speaking, there’s a clear classification that settles the debate once and for all: eels are fish.
Understanding the Habitat and Appearance of Eels
To begin with, one of the most notable distinctions lies in the eel’s preferred environment. Eels are typically found in shallow, muddy freshwater habitats such as swamps, rice fields, and slow-moving rivers. Unlike snakes, which can thrive in various habitats including forests and deserts, eels are bound to aquatic surroundings throughout their life cycle.
Moreover, their physical features further support their classification as fish. According to the book “Budi Daya Belut dan Sidat” by B. Sarwono, eels do not possess typical fins like many fish do. Their pectoral, dorsal, and anal fins have evolved into simple skin folds without fin rays, which give them a smooth, seamless body shape.
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Scientific Classification Places Eels in the Fish Category
Transitioning to a more scientific perspective, the eel’s taxonomic classification leaves no room for confusion. As outlined in Drs. Ruslan Roy’s book “Super Lengkap Budidaya Belut”, eels fall under the following taxonomy:
- Kingdom: Animalia
- Phylum: Chordata
- Class: Pisces
- Order: Synbranchiformes
- Family: Synbranchidae
- Genus: Monopterus
- Species: Varies by habitat
This classification confirms that eels are indeed vertebrate fish. Furthermore, Zoologi Vertebrata by Safrida emphasizes that all Pisces species live in water and breathe through gills, which also applies to eels.
Morphology and Anatomy Set Eels Apart
Despite being fish, eels have a morphology that differs significantly from most other fish species. Their cylindrical, elongated bodies resemble snakes, lacking prominent dorsal and pectoral fins. Their skin is slippery and scaleless, allowing them to move easily through muddy waters.
Interestingly, the color of an eel changes with age—young eels display a yellow-brown hue, while adults take on a darker brown tone. Their heads are typically round and large, equipped with tiny cone-shaped teeth and wide lips. Internally, their stomachs are notably large, thick, and elastic, enabling them to consume prey efficiently.
Varieties of Eels Found in Nature
In addition to their unique biology, eels also exist in several different types based on their habitats:
1. Swamp Eel (Synbranchus bengalensis)
Commonly found in mangrove forests and estuaries, swamp eels are known for their adaptability to brackish water. They are long and slender, possessing soft fin rays that help them maneuver through thick mud.
2. Rice Field Eel (Monopterus albus)
This species is widespread in agricultural regions. With a stout, short body and brown color, rice field eels can survive harsh conditions by burying themselves in dry mud when fields are drained.
3. Marine Eel (Macrotema caligans)
These eels live in coastal waters with sandy or rocky bottoms. They are easily identified by their small eyes located near the center of their mouths. Their dorsal fins align with their anal openings, helping them balance while swimming.
4. Horse Eel (Amphipnous cuchia)
The most fascinating of all, the horse eel has a lung-like organ under its neck that functions as an extension of the gill chamber. This allows the species to survive outside of water for extended periods. During dry seasons, they dig deep into the mud and hibernate until the rains return.
Eels Are Fish, Not Snakes
In conclusion, although their shape and movements resemble snakes, eels are undeniably fish. Their anatomy, behavior, and scientific classification under Pisces affirm this. So, the next time someone asks if an eel is a snake or a fish, you can confidently answer: it’s a fish—one with an extraordinary design tailored for life in muddy waters.