Top 10 Smallest Things In The World 2023

There is an ongoing debate about what truly is the smallest thing in the world; especially as it has been established that invisible particles like atoms and electrons can be divided. The debate does not immediately become easier when you make it the smallest living things in the world; this is because there is another raging argument about what exactly makes something alive.

In any case, there must be some form of answer to the question of the smallest things; it is remarkable that even respected journals have shied away from this topic.

Our focus will be natural world, rather than objects that have been fabricated by man; these are the most authentic anyway.

Top 10 Smallest Things In The World 2023

1. Nasuia Deltocephalinicola

The bacteria known as Nasuia deltocephalinicola was accidentally discovered in 2013 when a team of scientists were studying a pest; the European pest leaf-hopper, Macrosteles quadripunctulatus. It was measured to have a size of 112,091 nucleotides.

That is infinitely small; to compare for size just look at the human genome which measures 3.2 billion nucleotides.

This bacterium has a symbiotic relationship with the European pest leaf-hopper, Macrosteles quadripunctulatus; it lives in its gut; and helps it synthesize proteins from its diet which is the sap of leafy plants; which naturally only contains sucrose.

2. Nanoarchaeum Equitans

A marine single celled creature called Nanoarchaenum Equitans was discovered in 2002, in Iceland. It was discovered in a thermal vent; leading scientists to believe that it needs warm temperatures to survive. The single celled creature consists of a small circular creature which measures only 400 nm in diameter, making it one of the smallest known living organisms in the world.

It cannot synthesize its own food but must obtain it from a host, making it parasitic in nature. It also has a small filament which comes out of its circular body; and that is used to propel itself around.

3. Pelagibacter Ubique

Pelagibacter Ubique is a kind of bacteria; perhaps the smallest one known to live on its own, without needing to feed from a host. Pelagibacter Ubique measures between 370 to 890 nm (0.00037 to 0.00089 mm), and the diameter is 120 to 200 nm (0.00012 to 0.00020 mm).

This bacterium is a very important one; it inhabits the oceans where it plays a vital role in the balance of nature. It is said that this bacteria accounts for about 25% of all plankton cells; which means plankton feeding fish depend on this bacteria more than any other plankton; and that the entire ocean food chain rests on it.

4. Mycoplasma Genitalium

Mycoplasma Genitalium is another parasitic bacterium. This one lives in the bladder and waste disposal organs, as well as the genitals, and respiratory tracts of Primates. It is measured at 200 to 300 nm, making it one of the smallest known things in the world. Even more interesting is the fact that it is said to be the tiniest known organism that can grow independently, and reproduce.

5. Prasinophytes

The prasinophytes are a group of green algae that have only one single cell structure. Prasinophytes these are mostly marine plankton, although they also have some freshwater species. Many of these specimens are covered with organic scales, while others are naked.

Of particular interest is the genera known as Ostreococcus, which measures 0.8 μm (0.00080 mm) across; making it the smallest free-living eukaryote.

While they are the same species; there are some physical (morphological) differences because some have flagella extending out of their bodies while others do not.

6. Viruses

Viruses are diverse, but will be mentioned as one because there is some debate about whether they are actually living things, considering the fact that they do not have a cellular structure, and cannot metabolize on their own without the help of a host. However, they do have genetic material, and when they meet with a host they synthesize just fine.

The smallest viruses in terms of genome size are single-stranded DNA (ssDNA) viruses. Bacteriophage Phi-X174 measures 5,386 nucleotides. Porcine circovirus type 1 measures 1,759 nucleotides while some are known to measure 2000 nucleotides.

7. Mollusks

Condylonucula maya is a tiny species of saltwater clam which is found in the shallow waters in the Caribbean Sea off the coast of Mexico. It is a member of the family Nuculidae, which are known as the nut clams. It is a marine bivalve mollusk or micromollusk.

It is measured at about 500 μm (0.020 in) and is believed to be the smallest living bivalve.

8. Ammonicera Minortalis

Ammonicera minortalis is the worlds’ smallest water snail; it is measured at 0.32 to 0.46 mm (0.013 to 0.018 in), and was originally found in Cuba.

This animal is so tiny that it looks like a spec on the finger. It is usually colored brown, and is part of the marine food chain, making it a rather important animal.

9. Acmella Nana

Acmella Nana is a species of land snail measuring only 0.7 millimeters in size. The species was discovered in Borneo and Malaysia, back in 2015. The snails get their name from their size; nana is the Latin word for Dwarf.

It is the world’s smallest land snail as described by scientists Jaap J. Vermeulen and Thor-Seng Liew of the JK Art and Science in Leiden, and Institute for Tropical Biology and Conservation at the Universiti Malaysia Sabah respectively, and also Menno Schilthuizen of the Naturalis Biodiversity Center in Leiden.

The previous holder of the record was Angustopila dominikae, which measures 0.86 mm in size, and was described from China in September 2015.

10. Tiny Spiders

Spiders come next when it comes to the smallest creatures on earth; most Arachnids still extant today are small, leading some to believe that they have always been this way. It seems that they can get some encouragement when they see the spiders of the genus Symphytognathidae.

Males of Patu digua have a body length of 0.37 millimetres (0.015 inches), while the Samoan moss spider measures around 0.4 millimetres (0.016 inches) long.

The Frade cave spider known as Anapistula ataecina, may also be a contender for the world’s smallest spider; the females measure 0.43 mm (0.017 in) and the males 0.48 mm (0.019 in).



The smallest things in the world which cannot be divided into even smaller specimens are living things; most of which can only be seen with the help of a microscope. These records are not final; more discoveries are been made regularly, and so even smaller organisms may soon be discovered.