We have traveled from the surface to the depth of the ocean to create this consolidated list of smallest sea creatures with facts. They are unbelievably tiny!

List of Smallest Sea Creatures

small sea creatures

Squat Shrimp – Maxium Length 13 mm (.5 inch)

Squat Shrimp or Sexy Shrimp are small and colorful. The funny name comes from their habit of holding their abdomen above their head and wagging the tail. 

They are usually translucent brown in color with white circles around their body.

image of a squat shrimp - one of the smallest sea creature
photo – Flickr
Lifespan3 years
DietHost anemone’s tentacles and the planktonic organisms (in the wild)
Algae and brine shrimp (in aquariums)
Habitat:Indian, Pacific, and Parts of Atlantics Ocean

Fun Facts:

  • Usually, five-eight squat shrimps live on a single anemone. They hide under the anemone if feeling threatened.
  • They move away from their anemone at night, for feeding
  • These species are all born males. The larger ones turn into females slowly.
  • They are also nicknamed cleaner shrimp, as they clean their homes, other creatures mouths. They are popular in fishtanks, since they keep the tank clean.
  • Squat shrimps are usually not scared by humans.

Pink Eye Goby – length 2 cm

close picture of a pink eye goby - a small ocean fish
image: Rickard Zerpe, via Wikimedia Commons

Pink Eye Goby is one of the cutest-looking sea animals. The translucent body has yellow organs that can be seen through. The eyes are of vivid pink color.

They like to hover and sit on the tips of the coral, so they are easy enough to photograph.

Lifespanfew years
Dietsmall crustaceans, zooplankton
Habitat:Acropora corals in the shallow Indo-Pacific area

Fun Facts:

  • The fish is so transparent that one can see the bones through its body.
  • The species is also referred to as Purple-eye Goby, Red-eyed Goby, Reef Goby.

Dwarf Lantern Shark – approx length 6.1 inches

Dwarf Lantern Shark is the smallest known shark in the world. It is rarely seen as this species lives in the dark sea.

Like other deep-sea animals, it has the ability to glow in the dark. Their long flattened head occupies one-third of their body.

Weight0.3 lbs
Lifespan20-30 years
Dietsmall crustaceans, krill, zooplankton, smaller fish
HabitatCaribbean sea – at around 300-900 meters down in the dark ocean

Fun Facts:

  • Dwarf Lantern Sharks attract their prey by glowing in the dark.
  • The females give birth to 2-3 babies.
  • Their conservation status is unknown, this being deep water fish.
  • They communicate nonverbally – by opening jaws, angling bodies, gesturing their heads.
  • A baby dwarf lantern shark is called a pup.

In News:

Read about the new smallest shark discover – The American pocket shark.

Red Lip Blenny – length 4 inches

image of a redlip benny, one of the tiniest animal of the sea.
image: Matthew Hoelscher (Flickr)

Red Lip Blenny is known so because of its red color lip and tinge of red in the fin. They are also known as Black Blenny, Coral Blenny, etc.

They are chocolate brown in color.

Lifespan2-4 years
Dietprimarily algae
Habitat:coral crests and shallow reefs – Eastern Atlantic

Fun Facts:

  • Red lip Blenny is known the attack intruders with their sharp canine teeth.
  • Like most other fish species, the male is the primary caregiver of the eggs.
  • Redlip Blennies do not have any swimbladder.

Juvenile Frogfish – length 1.8 – 22 inches

Juvenile Frogfish bears many similarities to frogs and thus it is named so. The frogfish transform drastically with age.

The Juveline frogfish has ornate markings with scattered orange spots on its black body. Once reaching adulthood, its color changes completely.

Lifespan20 years
Dietcrustaceans, congeners, and small fish
Habitat:Tropical and subtropical waters (Indo-Pacific ocean & the Red sea)

Fun Facts:

  • They camouflage to match their coral surroundings.
  • Their camouflage helps them attract prey and ward off predators.
  • Frogfish takes days to week for changig colors.

Irukandji jellyfish – 1-2 cm in diameter

Irukandji jellyfish is the tiniest and one of the deadliest creatures of the sea. Their sting results in life-threatening Irukandji syndrome.

They have four tentacles that can grow to 0.4-40 inches. Their tentacles and the body are coated with stinging cells known as nematocysts.

Lifespannot known
Dietnon-insect arthropods, other marine invertebrates
Habitat:Northern Australia

Fun Facts:

  • The name Irukandji is given after an aboriginal tribe that lives in northern Queensland. They have been suffering from the attack but did not know the cause, till a scientist found it.
  • Irukandji jellyfish are fast swimmers.
  • Baby Irukandji jellyfish are referred to as ephyrae.
  • It camouflages in the water easily as it is transparent. Hence it is also known as invisible killer.

In News:

Woman stung by Irukandji Jellyfishread more.

Cherub Fish – Length 3.2 inches

image of a Cherub fish - a small ocean animals
image: Brian Gratwicke, Wikimedia Commons

The Cherub fish has a small mouth with a short, blunt snout. Its body is deep, oval, and compressed.

Cherub fish come in a variety of colors – red, gray, blue, and yellow. They look cute with tall, pointed fins.

Lifespan5 years
Dietalgae and small benthic invertebrates
Habitat:Corals in the Western Atlantic (Bermuda to Florida), the Caribbean Sea, Gulf of Mexico

Fun Facts:

  • Cherub fish use chemicals in their urine and bile to communicate.
  • They are slow swimmers and can not tolerate strong water currents.
  • A baby Cherub fish is called a fry.
  • They are quite aggressive.

Octopus Wolfi – length 2.5 cm

Wolfi octopus is the world’s smallest octopus.

Weight< 1 gm
Lifespan6-18 months
Dietsmall crustaceans, mollusks, krill 
Habitat:Shallow waters of the western Pacific

Fun Facts:

  • Wolfi octopus is colorblind like other octopuses, But they are blessed with good eyesight that helps them catch prey.
  • The wolfi octopus is capable of laying multiple batches of eggs.
  • Their conservation status is quite secure and do not list in endangered species.

Krill – length 1-6 cms

Krill form a very important part of the ocean food chain. They are the main diet of most marine predators – whales, penguins, seals, seabirds, other fish.

They are called the keystone species in the South Antarctic ecosystem.

Weight approx 1 gm
Lifespan10 years
Diet phytoplankton, microscopic, single-celled plants
Habitat:All the oceans, particularly in the Antarctic

Fun Facts:

  • There are 85 known species of Krill.
  • 500 million tons of krill are present in the Southern Ocean.
  • Krill spend the daytime in the deep ocean to avoid being eaten.
  • Krills live in large swarms as a defense against predators.

Few Other Small creatures of the Ocean

Acentrounura is species of pygmy pipehorse. They grow up to a length of 2-3 inches only. They look like cute adorable worms.

Like any other seahorse, Acentrounura males carry their live offsprings in a special pouch in their bodies.

Pygmy Seahorse grows to a maximum length of 2.4 cm. They camouflage easily and are known to take the color of the species they live on.

Nudibranchs are known for their extraordinarily colorful bodies. They can be from 0.25 inches to 12 inches.

Zooplankton are small floating organisms that drift in the water. These animals live all or part of their lives drifting. Most of them are 200-400 µm long.