Acanthuridae
Orangespot surgeonfish
Acanthurus olivaceus
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.
Orangespot surgeonfish
Carangidae
Orangespotted trevally
Flavocaranx bajad
Monacanthidae
orangetail filefish
Pervagor aspricaudus
Cyprinidae
Orangetail shiner
Pteronotropis merlini
Pomacentridae
Orbicular Damselfish
Amblyglyphidodon orbicularis
Apogonidae
orbiculate cardinalfish
Sphaeramia orbicularis
Chaetodontidae
Oriental butterflyfish
Chaetodon auripes
Uranoscopidae
Oriental fringe stargazer
Ichthyscopus pollicaris
Labridae
Oriental maori wrasse
Oxycheilinus orientalis
Haemulidae
Oriental Sweetlips
Plectorhinchus vittatus
Labridae
Ornamented wrasse
Halichoeres ornatissimus
Pomacanthidae
Ornate angelfish
Genicanthus bellus
Chaetodontidae
Ornate butterflyfish
Chaetodon ornatissimus
Galaxiidae
Ornate Galaxias
Galaxias ornatus
Engraulidae
Osbeck's grenadier anchovy
Coilia mystus
Cichlidae
Oscar
Astronotus ocellatus
Pomacentridae
Outer-reef damsel
Pomacentrus emarginatus
Bothidae
oval flounder
Bothus myriaster
Gobiidae
Oval-spot goby
Asterropteryx ovata
Holocentridae
Ovaleye soldierfish
Ostichthys ovaloculus
Pomacentridae
Ovate chromis
Pycnochromis ovatiformis
Carangidae
oxeye scad
Selar boops
Epinephelidae
Pacifc insular grouper
Epinephelus insularis
Pomacentridae
Pacific anemonefish
Amphiprion pacificus
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.