Unknown species found at the Makapu’u tidepools on the Hawaiian island of O’ahu.
It’s almost certainly a member of the scorpionfish family, which is easy to recognize from the bony protrusion under the eye. It looks similar to sea robins, which also have modified pectoral fins for “walking” on the sea floor.
Looks like an armored searobin, which is in that family. It’s a deep sea fish, so why it would be in a tide pool? we don’t know for sure.
Barracuda, Pennekamp Coral Reef State Park
by PMC
Mola Mola by Sebastian Sans
Say Cheese - Cascade Mall, Indonesia
by Diyana Kamaruza
Encounter
by cuellar
The Angler fish is an ambush predator (spot the lure projecting from it’s head that it uses to attract fish to within striking distance of it’s mouth) and is normally found on the sea bed. 
riordan_david
A school of Bangaii Cardinal fish
by sjnewton
Group of small fish trying to escape from a group of larger fish.
by Hooper Project
Flying fish, South Atlantic Ocean off of Angola, Africa.
by Jack Swenson
A streamlined torpedo shape helps flying fish generate enough speed to break the water’s surface, and large, wing-like pectoral fins help get them airborne.
by Graham Ekins

This is juvenile of turbot (Psetta maxima), coloured for bones (red) and cartilage (blue). Done as a prodject in fishbiology.
by Dísin
What a fish sees
by smoothtrooper1
Duck and Carp at a pond in the Chinese Garden in Frankfurt am Main, Germany
by Xindaan
one fish, two fish…
by •Sarah P•