Ophichthidae
redsaddled snake eel
Quassiremus nothochir
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.
redsaddled snake eel
Cyprinidae
Redside dace
Clinostomus elongatus
Gobiidae
Redspeckled dwarfgoby
Eviota rubrisparsa
Chaenopsidae
redspine blenny
Emblemariopsis occidentalis
Cyprinidae
Redspot barb
Enteromius kerstenii
Apogonidae
Redspot cardinalfish
Ostorhinchus dispar
Apogonidae
Redspot cardinalfish
Ostorhinchus parvulus
Microdesmidae
Redspot dartfish
Ptereleotris rubristigma
Gobiidae
Redspot dwarfgoby
Eviota rubrimaculata
Pinguipedidae
Redspot sandperch
Parapercis rubromaculata
Labridae
Redspot wrasse
Pseudocoris yamashiroi
Scyliorhinidae
Redspotted catshark
Schroederichthys chilensis
Pinguipedidae
Redspotted sandperch
Parapercis schauinslandii
Gobiidae
Redspotted shrimpgoby
Amblyeleotris ogasawarensis
Gobiidae
Redstripe goby
Grallenia rubrilineata
Syngnathidae
Redstripe pipefish
Dunckerocampus baldwini
Cyprinidae
redstripe rasbora
Trigonopoma pauciperforatum
Epinephelidae
Redstriped basslet
Liopropoma tonstrinum
Osphronemidae
Redtail Licorice Gourami
Parosphromenus ornaticauda
Pinguipedidae
Redtail sandperch
Parapercis rubricaudalis
Cyprinidae
Redtail Sanjika
Opsaridium ubangiense
Tripterygiidae
Redtail triplefin
Enneapterygius rubicauda
Plesiopidae
Redtip longfin
Plesiops verecundus
Polypteridae
reedfish
Erpetoichthys calabaricus
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.