Synbranchidae
Blind cave eel
Ophisternon candidum
FISH SPECIES
Long-bodied Fish
Explore fish with elongated, anguilliform or ribbon-like silhouettes, and learn how length changes locomotion and foraging.
FISH ATLAS / FIELD GUIDELong Bodied FishIN THIS CHAPTER01 / Characteristics02 / Lifestyle03 / Species04 / Field notes
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01 / NATURAL HISTORY
Characteristics
Elongated body plans reduce hydrodynamic drag, allow passage through tight apertures, and feature reduced or absent pelvic fins combined with extensive multi-vertebral muscular flexing systems.
- 01Anguilliform wave propulsion
- 02Crevice & conduit navigation
- 03Reduced appendages & low drag
02 / LIFESTYLE
Lifestyle
True eels swim via full-body anguilliform waves, sending lateral bends down their entire length to push against water, allowing them to reverse direction inside narrow subterranean burrows. Needlefish and pikes maintain a rigid elongated torso, keeping the body straight until their posterior fins and muscular caudal peduncle unleash sudden, explosive forward lunges.
OBSERVATION INDEX
- Full-body anguilliform undulation
- Reverse movement inside burrows
- Rigid body ambush alignment
03 / SPECIES
Representative species
Discover representative species illustrating the ecological diversity, morphologies and adaptations of this group.
Blind cave eel
Nemacheilidae
Blind cave loach
Nemacheilus troglocataractus
Eleotridae
Blind gudgeon
Milyeringa veritas
Nemacheilidae
Blind loach
Eidinemacheilus smithi
Mastacembelidae
Blind spiny eel
Mastacembelus brichardi
Dinematichthyidae
Blindfish
Dactylosurculus gomoni
Ophichthidae
Blistered snake eel
Callechelys papulosa
Trichonotidae
Bloch's sand diver
Trichonotus blochii
Cichlidae
Blockhead Cichlid
Steatocranus tinanti
Gobiidae
Blotch-tailed pygmygoby
Trimma caudomaculatum
Clariidae
Blotched catfish
Clarias stappersii
Pentanchidae
Blotched catshark
Asymbolus funebris
Opistognathidae
Blotched jawfish
Opistognathus latitabundus
Muraenidae
Blotched moray
Uropterygius fasciolatus
Amphiliidae
Blotched sand catlet
Zaireichthys conspicuus
Ophichthidae
blotched snake eel
Callechelys muraena
Ophichthidae
Blotched snake-eel
Ophichthus erabo
Channidae
Blotched Snakehead
Channa maculata
Tripterygiidae
Blotched triplefin
Enneapterygius ventermaculus
Muraenidae
blotched-neck moray
Gymnothorax margaritophorus
Callionymidae
blotchfin dragonet
Callionymus filamentosus
Percidae
Blotchside logperch
Percina burtoni
Exocoetidae
Blotchwing flyingfish
Cheilopogon hubbsi
Scyliorhinidae
Blotchy swell shark
Cephaloscyllium umbratile
04 / FIELD NOTES
A closer look
Why do eels and morays lack pelvic fins?
Pelvic fins create hydrodynamic drag and easily catch on obstructions when navigating tight crevices, burrows and rock cracks. Over evolutionary time, appendages were reduced or lost in favor of continuous median fins.
How do elongated fish like gar and needlefish hunt?
Rather than undulate their whole bodies, they hold their long torsos completely straight to resemble floating sticks or debris, then unleash rapid lateral head snaps or tail bursts to impale unsuspecting prey on their toothed jaws.