Epinephelidae
Sixbar grouper
Epinephelus sexfasciatus
FISH SPECIES
Flat-bodied Fish
Compare fish with laterally compressed, dorsoventrally depressed or asymmetrical body plans across habitats.
FISH ATLAS / FIELD GUIDEFlat FishIN THIS CHAPTER01 / Characteristics02 / Lifestyle03 / Species04 / Field notes
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01 / NATURAL HISTORY
Characteristics
Flattened body forms represent two distinct evolutionary paths: laterally compressed forms engineered for agility in narrow vertical spaces, and dorsoventrally depressed or asymmetrical forms specialized for living flush against the ocean floor.
- 01Laterally compressed maneuvering
- 02Dorsoventrally flattened resting
- 03Benthic sediment concealment
02 / LIFESTYLE
Lifestyle
Laterally compressed fishes like butterflyfishes and batfishes orient vertically to dart through intricate reef branches, using broad median fins to execute instantaneous, low-radius pivot turns. In stark contrast, depressed rays and asymmetrical flatfishes bury beneath sediment with only elevated eyes exposed, remaining completely motionless until striking passing prey from underneath.
OBSERVATION INDEX
- Zero-radius turns in structural cover
- Sediment concealment with raised eyes
- Undulatory pectoral propulsion on bottoms
03 / SPECIES
Representative species
Discover representative species illustrating the ecological diversity, morphologies and adaptations of this group.
Sixbar grouper
Labridae
Sixbar Wrasse
Thalassoma hardwicke
Chaetodontidae
Sixspine butterflyfish
Parachaetodon ocellatus
Alosidae
skipjack herring
Alosa chrysochloris
Carangidae
Skipjack trevally
Pseudocaranx wrighti
Pomacentridae
skunk clownfish
Amphiprion akallopisos
Acanthuridae
sleek unicornfish
Naso hexacanthus
Bathylagidae
slender blacksmelt
Bathylagus pacificus
Congridae
slender conger
Uroconger lepturus
Ophidiidae
slender cuskeel
Porogadus miles
Pomacentridae
slender damselfish
Pomacentrus leptus
Gempylidae
slender escolar
Paradiplospinus gracilis
Trichiuridae
Slender frostfish
Benthodesmus tenuis
Caesionidae
slender fusilier
Gymnocaesio gymnoptera
Gerreidae
slender silver-biddy
Gerres oblongus
Microstomatidae
Slender Smallmouth
Microstoma australis
Gobiidae
Slender spongegoby
Phyllogobius platycephalops
Dorosomatidae
slender thread herring
Opisthonema bulleri
Acanthuridae
slender unicorn
Naso minor
Dorosomatidae
Slender white sardine
Escualosa elongata
Labridae
Slender wrasse
Pseudocoris petila
Bythitidae
Slimy cuskeel
Brosmophyciops pautzkei
Labridae
sling-jaw wrasse
Epibulus insidiator
Sciaenidae
Small lunate caudal fin croaker
Atractoscion atelodus
04 / FIELD NOTES
A closer look
What is the evolutionary difference between a ray and a flounder?
A ray is a cartilaginous fish flattened from top to bottom (dorsoventrally depressed) with eyes on top and gill slits on the underside; a flounder is a bony fish that lies on its side, whose eye migrates during larval development to make the body asymmetrical.
Why do disk-shaped fish like angelfish and discus have tall bodies?
A laterally compressed disc shape provides high vertical stability and exceptional turning agility, allowing fish to twist into narrow vertical crevices and maneuver between tangled roots or coral branches without losing control.