This Massive Cetacean grows up to 100 feet in length and can weigh up to 200 tonnes. It is the largest mammal known to exist and is found scattered across every ocean in the world. During Summers, they migrate to Antarctica.
(By Tab59 - Flickr: Ballet de Rorquals dans la baie de St Laurent au Québec, CC BY-SA 2.0)
This Colossal creature is second largest only to the Blue Whale and is also found in all oceans. It is also commonly known as the Common Rorqual or the Herring Whale.
Humpback Whales, though more popular, are roughly half to quarter the size of Blue Whales, growing up to 60 feet and weighing no more than 40 tonnes. They are especially well known for their long migrations, with one setting a record in 2010, migrating a whopping 6200 miles from the Coast of Brazil to Madagascar.
(By Charles J Sharp - Own work, CC BY-SA 4.0)
This cetacean loves deep waters and prefers tropical and subtropical climates. They are also known as the Dwarf Fin Whale or the Pygmy Bryde's Whale. They are mostly found off the coasts of the majority of Southeast Asian Countries and Australia.
(By Salvatore Cerchio et al. / Royal Society Open Science - Royal Society Open Science, CC BY 4.0)
This massive creature is another expert migrator and can travel up to 12600 miles during the migratory season. This species used to be heavily hunted for its oil, especially between the 17th Century and the 20th Century, and in fact, nearly went extinct due to overexploitation.
Cetaceans of the Channel Islands National Marine Sanctuary, Public Domain)
These little guys, hiding from the camera, prefer colder climates and tend to migrate from Tropical habitats to more moderate and cold ones. There are two types of Minke Whale, one of which is the Common Minke Whale, depicted below and above here, and the other is the Antarctic Minke Whale.
These beautiful strokes of black and white tend to spread themselves from the Bering Sea to the Southern Coast of California and into the waters approached Mexico. This beauties generally tend to prey on other species of whales, even larger ones. That's why they are also commonly known as Killer Whales.
This is one unique looking friend of the fish, with its pale white skin and incredible forehead. Maybe the white can be attributed to their preference for the cold, as this species is most frequently found in the Arctic Ocean and the surrounding waters. It belongs to the same family as the Narwhal.
This is one of the most intelligent species on this planet. Its bodies have even adapted over time to allow them to breathe underwater, using their blowholes. They are major prey of tiger sharks, great white sharks, and other larger predators. There are only 600,000 of these beauties left worldwide.
These fun creatures are big dolphins with virtually no snout and an interesting appearance with markings on their skin, as you can see. They are happiest in temperate and tropical waters and tend to stick nearest to continental shelves.
This flash of blue and yellow prefers the murky coral reefs of the western Indo-Pacific Ocean, and are scattered across the coasts of East Africa, as well as numerous places across Southeast Asia and Japan.
Another inhabitant of the Indo-Pacific Ocean, these algae eaters have interesting behavioral traits. The young tend to hide in holes near rocks and reefs while the older and bolder ones slowly move further out to the front holes of the reefs.
This spotted fish is found all across the Atlantic Ocean, the Indian Ocean, and the Pacific Ocean. They are well-known favorites to keep as pets as they adapt well to captivity.
These friendly looking fish come in all different colors, shapes, and sizes. They are mostly found in the Gulf of Mexico and like to make their way through deep and shallow waters. Leave no water unturned!
Another unique-looking grouper fish, most common to the East Indian Ocean, and another heavy favorite in the pet trade. It likes to stick to rocky areas and is also found near coral reefs.
This stylish silver swimmer is yet another popular character you'll find in the pet trade and see in numerous home aquariums. Their natural habitats, however, are off the coasts of Australia and spread across the Western Indo-Pacific ocean.
This gecko of the ocean is found everywhere from the East African coast of the Indian Ocean to Somoa, across the Red Sea and the Great Barrier Reef. They generally tend to enjoy their little, hidden holes and stick to reef flats and seaward reefs or shallow lagoons embedded with either rubble, coral or sand.
This brightly colored type of Boxfish seems to be perpetually pouting. Another inhabitant of the Indo-Pacific ocean, this strange looking friend of ours stays close to bays and ports and prefers muddy or sandy habitats.
Most of you have seen at least caricatures of this funny fish on TV. When the Porcupine Pufferfish is threatened, it tends to immediately expand, thereby releasing a series of sharp spines embedded into its skin. The spines are non-poisonous but pretty sharp and plenty scary!
Hello, my brightly shaded woodpecker of the sea. When this fish isn't in yet another home aquarium, this type of Butterflyfish is found usually at a depth of 25 meters in coral reefs as well as at rocky shorelines.
These fish are hard to separate. While they are two distinctly different species, they are close relatives of each other, from the same family of species. Whether in their natural habitat or in aquariums, these fish tend to stick to groups.
This tiny tropical fish has been an extremely popular fish for both the legal and illegal pet trade and is seen in record numbers in aquariums. They have been circulated in the trade since 1990, and are still at high risk of overexploitation.
I am sure many will recognize this blue-green silver-ish friend of ours. It probably goes by more names than can ever be recorded, but it's a common household pet. It originates from the South and Indo-Pacific ocean, mostly in lagoons and off larger shores.
Everybody, don't worry. I found Nemo. Chilling in the Anemone. Which is the name of the plant like coral that clownfish often live in, that provides them a protective barrier and hiding place from predators and helps to remove parasites.
This monstrous gorgeous unbelievable marvels of nature are my absolute favorite. Just look at that face. Should I be afraid? Should I be amused? Should I be in awe?
I'd go with a little bit of all three. These beautiful creatures are amongst the most dangerous in the sea and are highly venomous.
Found in the Red Sea and Indo-Pacific Ocean, the unique appearance of the Lionfish makes it an expert camouflager. these fish lie as deep as 300 feet below sea level, burying themselves into hard ground.
(By United States. National Marine Fisheries Service - https://archive.org/details/cetaceansofchann00leat 
