Batrachoididae
Grunting toadfish
Allenbatrachus grunniens
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.
Grunting toadfish
Percidae
Guadalupe darter
Percina apristis
Cyprinidae
Guadalupe roundnose minnow
Dionda nigrotaeniata
Sphyraenidae
guaguanche
Sphyraena guachancho
Rivulidae
Guanabara Rivulus
Atlantirivulus guanabarensis
Callichthyidae
Guaramiranga cory
Aspidoras rochai
Halosauridae
Guenther's halosaur
Halosaurus guentheri
Cyprinidae
Guercif barbel
Luciobarbus guercifensis
Pristigasteridae
Guiana longfin herring
Odontognathus mucronatus
Ophidiidae
Guianan cusk-eel
Ophidion guianense
Belonidae
Guianan Needlefish
Potamorrhaphis guianensis
Sciaenidae
Guinea croaker
Pseudotolithus epipercus
Sphyraenidae
Guinean barracuda
Sphyraena afra
Polypteridae
Guinean bichir
Polypterus ansorgii
Congridae
Guinean conger
Paraconger notialis
Muraenesocidae
Guinean pike conger
Cynoponticus ferox
Rhinobatidae
guitarshark
Rhinobatos rhinobatos
Engraulidae
Gulf anchovy
Anchoa helleri
Blenniidae
Gulf blenny
Ecsenius pulcher
Dinematichthyidae
Gulf brotula
Ogilbia ventralis
Chimaeridae
Gulf Chimaera
Hydrolagus alberti
Cyprinidae
Gulf chub
Macrhybopsis tomellerii
Synaphobranchidae
Gulf Cutthroat Eel
Synaphobranchus oregoni
Myxinidae
Gulf hagfish
Eptatretus springeri
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.