Amazonian leaf fish Monocirrhus polyacanthus
The green-gold vertical bars and long fin appendages help camouflage juvenile lookdowns in sea grass.
Not only does this strategy help young fishes avoid predation, but in fact it makes adult tripletails very effective ambush predators. By mimicking a lifeless bit of flotsam around structure, tripletails drift slowly at an odd angle amongst unsuspecting fishes and shrimp feeding on or using the structure for cover, then use their large protrusible mouths to create enormous suction that inhales their prey. In captivity, the tripletails display this instinctive behavior and "hide" in plain sight, drifting listlessly near a support beam until feeding when they become aggressive and active.
The two tripletails shown in the video ( ~ 16" long) are in a grow-out tank and hopefully will grow large enough to one day be floating strangely near the surface of our Chesapeake Bay Aquarium, slightly sideways and barely moving, prompting visitors to ask in concern "what's wrong with that fish?" Nothing, it's a tripletail, that's what they do.