This Fugly little guy looks like he fell in a big mud puddle, but that caked-on mud look is just his camouflage. His whole family of species and subspecies are visually challenged and every last one of them is seriously fugly.
Frogfish hardly seem to be fish at first glance -- they are stocky, lumpy, and sometimes spiny. They tend to live on the ocean floor around rocks and coral reefs. They are also known as anglerfish, especially in Australia. Their very "fugliness" is designed to hide them from predators or to lure in prey. Some are even covered in algae. Their aggressive camouflage is so accurate that sea slugs have been known to crawl right over them. They are also known to be able change color.
Frogfish are found in most of the tropical and subtropical waters of the world, with the most notable exception being the Mediterranean Sea. They are often found in public aquariums and occasionally in private ones. They are difficult to keep since they often refuse food in captivity.