Apogonidae
Humpbacked cardinalfish
Yarica hyalosoma
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
SCROLL
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.
Humpbacked cardinalfish
Ambassidae
Humphead Glassfish
Parambassis pulcinella
Engraulidae
Humphead thryssa
Thryssa polybranchialis
Labridae
Humphead wrasse
Cheilinus undulatus
Pempheridae
Hurghada sweeper
Pempheris shirleen
Batrachoididae
Hutchin's toadfish
Halophryne hutchinsi
Anthiadidae
Hutomo's anthias
Pseudanthias hutomoi
Apogonidae
Hyaline cardinalfish
Foa hyalina
Pempheridae
Ibo sweeper
Pempheris ibo
Gobiidae
Imai's pygmygoby
Trimma imaii
Pomacentridae
Imitator damsel
Pomacentrus imitator
Pomacentridae
Immaculate damsel
Mecaenichthys immaculatus
Pseudochromidae
Immaculate dottyback
Pseudoplesiops immaculatus
Gobiidae
Imperial goby
Platygobiopsis akihito
Bothidae
imperial scaldfish
Arnoglossus imperialis
Mullidae
Inayat’s goatfish
Parupeneus inayatae
Epinephelidae
Incandescent basslet
Liopropoma incandescens
Gobiidae
Incognito goby
Gobius incognitus
Engraulidae
Indian anchovy
Stolephorus indicus
Ariommatidae
Indian ariomma
Ariomma indica
Cepolidae
Indian bandfish
Owstonia whiteheadi
Symphysanodontidae
Indian Bunquelovely
Symphysanodon xanthopterygion
Apogonidae
Indian cardinalfish
Apogon indicus
Pomacentridae
Indian damsel
Pomacentrus indicus
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.