Pomacentridae
threeline damsel
Pomacentrus trilineatus
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.
threeline damsel
Labridae
threeline rainbowfish
Stethojulis trilineata
Synagropidae
Threespine bass
Caraibops trispinosus
Malakichthyidae
Threespine cardinalfish
Verilus anomalus
Pomacanthidae
threespot angelfish
Apolemichthys trimaculatus
Pomacentridae
Threespot chromis
Chromis verater
Pomacentridae
threespot damsel
Pomacentrus tripunctatus
Pomacentridae
threespot damselfish
Stegastes planifrons
Epinephelidae
Threespot grouper
Epinephelus trimaculatus
Holocentridae
threespot squirrelfish
Sargocentron cornutum
Labridae
Threespot wrasse
Halichoeres trimaculatus
Badidae
Tiger Badis
Badis kyar
Pseudochromidae
Tiger dottyback
Pseudochromis tigrinus
Poeciliidae
Tiger Limia
Poecilia islai
Gobiidae
Tiger Mangrove Goby
Mugilogobius tigrinus
Nemacheilidae
Tigris loach
Oxynoemacheilus tigris
Cichlidae
tilapia
Sarotherodon galilaeus
Carangidae
tille trevally
Caranx tille
Apogonidae
Timor cardinalfish
Apogonichthyoides timorensis
Gobiidae
Tiny goby
Lubricogobius nanus
Gobiidae
Tiny shrimpgoby
Mahidolia paucipora
Macrouridae
Tiny whiptail
Pseudonezumia pusilla
Pempheridae
Tiran sweeper
Pempheris tiran
Dorosomatidae
Toli shad
Tenualosa toli
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.