The Tamagotchi species comes in a variety of different subspecies. each with their own unique characteristics that distinguish them from the standard Tamagotchi. However, they retain several key characteristics of Tamagotchi, such as the capability of Evolution.
Angels (てんしっち Tenshitchi) are a subspecies that acts as part of the Tamagotchi afterlife. Angels are born when a Tamagotchi dies, and their spirit, Obaketchi, evolves into Ghost Jr. They live in the Tenshitchi Capital, often have wings and/or a halo, and spend their time praying for the health and safety of the living Tamagotchis. Leaving the Capital gradually consumes energy from them, preventing them from leaving for very long. They are sworn enemies with the Deviltchi, and often have to stop the Devils from causing chaos or tempting weaker Angels into turning evil.
Angels are raised on the Tamagotchi Angel, and can also be observed in Hoshi de Hakken!! Tamagotchi. Names in English end in "Angel", with the exception of Ghost Jr. In Japanese, names end with "tenshi" (てんし) or "ten" (てん). "Tenshi" is the Japanese word for "Angel".
Deviltchi (デビルっち Debirutchi) is a subspecies that acts as part of the Tamagotchi afterlife. Deviltchi are born when neglected Angels stray away from their angelic duties, or are tempted to perform evil by other Deviltchis. They only have four stages of life (three standard and one special), and can live for a lot longer than most subspecies. They reside in the Devil World. Deviltchis usually either have pointed horns or black wings, although sometimes they can have both or neither. For an entertainment fix, Deviltchis like to spend their time bullying and harassing young Angels.
Deviltchi can be raised on the Debirutch no Tamagotch. Names in English will either end with "Deviltchi" (such as Girl Deviltchi), or have Devil in front of their name (such as Devil Mametchi) if they are a Devil counterpart to a normal Tamagotchi. Names in Japanese will either end with debiru (デビル) or debirutchi (デビルっち), or have debiru within the name. "Debiru" is the Japanese word for "devil".
Mushitchi (むしっち) is a subspecies that is comprised of bug-like Tamagotchi. They live primarily in the Mushitchi Forest (though can be found all over the planet) and are nearly invisible to the naked eye, which makes them vulnerable to being accidentally stepped on. Despite their small size and bug-like features, they are as sentient as a regular Tamagotchi.
Sakanatchi (さかなっち) is a subspecies that is comprised of fish-like Tamagotchi. They are born and raised in the Sakanatchi Sea, and can be found all over the planet. They are vulnerable to attacks from polar bears. Like the Mushitchi, they are as sentient as a normal Tamagotchi.
Sakanatchi are raised on the Tamagotchi Ocean and Game de Hakken!! Tamagotchi 2, and can also be observed in Hoshi de Hakken!! Tamagotchi. The name comes from the Japanese word sakana (魚), which means fish.
Akai (赤い) Tamagotchi is a subspecies of Tamagotchi that resemble normal Tamagotchis, except their outlines are red instead of black or navy blue. They reside in Makkakka Town, a perpetually hot environment with rivers of red wine. A Tamagotchi born in Makkakka Town will always be an Akai Tamagotchi, while a normal Tamagotchi that spends a significant amount of time in Makkakka Town (especially if they swim in the rivers) may become one. For some Tamagotchis that have cooler body colors (such as Kurokotchi), they may have their body color more violet or red as an Akai Tamagotchi. On the Tamagotchi m!x, the red outline is a genetic trait that can be passed on to the next generation.
The standard Tamagotchi naming conventions apply to Akai Tamagotchi. If they are an Akai variant of a normally non-Akai Tamagotchi, they may sometimes be referred to with "Akai" before their name, although they are not counted as a separate species due to how Akai Tamagotchi are formed.
Ura Tamagotchi (ウラたまごっち) is a subspecies of Tamagotchi that resemble normal Tamagotchis, except that their outlines are turquoise blue instead of black or navy blue. They reside in Uratama Town, which is located inside the Tamagotchi Planet's mouth and it is therefore dark 24 hours a day. A large number of Ura Tamagotchis are opposite counterparts to regular Tamagotchis. For example, a lazy Tamagotchi, such as Kuchipatchi, will have an Ura counterpart that's more lively, such as Ura Kuchipatchi. A Tamagotchi can evolve into and out of the Ura subspecies (as demonstrated on the Tamagotchi Connection Version 4.5 and Tamagotchi iD L 15th Anniversary Version), and can breed with non-Ura Tamagotchis with no ill effect. On the Tamagotchi m!x, the blue outline is a genetic trait that can be passed on to the next generation.
The standard Tamagotchi naming conventions apply to Ura Tamagotchis; however, if they are a counterpart of a normal Tamagotchi, they will have "Ura" (ウラ) in front of their name.
Costume characters are a species of Tamagotchi that only exist when another adult character uses a costume item. Once an adult wears the costume, their personality will change to match the new form. However, their favorite foods and sleeping times will remain unchanged. Costume characters have no special naming conventions.
On the Keitai Kaitsuu Tamagotchi Plus and Akai, the costume item was exclusive to Kurokotchi (turning it into Wooltchi), and would remain on until the item was used again. Costumes on the Tamagotchi Connection Version 2, Version 3, and Tamagotchi Music Star can be worn by any adult, but the adult will remove the costume once they go to sleep. Additionally, some costumes are one-time use items and must be bought again after being used, while others can be used perpetually.
A My Tama (ナウたま Nautama) is a special kind of Tamagotchi born from m!xing. When two adult Tamagotchi characters marry, the offspring will inherit a mix four of the parents' physical traits: the body (head, torso, and mouth), eyes, headgear (such as hair, ears, or hats), and miscellaneous accessories (such as wings, capes, tails, etc.). It can also inherit body and outline colors, including those of Akai and Ura Tamagotchis. The genetics inherited influence the My Tama's favorite foods and items, as well as what time it falls asleep.
My Tamas follow the standard naming convention of having "-tchi" (っち) at the end of their name. However, the user is required to provide the name. My Tamas were introduced on the Tamagotchi m!x in Japan and on the Tamagotchi On internationally.
Iyatchi (いやっち) is a subspecies of Tamagotchi that have a more violent and ruthless disposition than a normal Tamagotchi. Iyatchis have not appeared on any virtual pets, although they appear on the packaging for nearly every vintage Japanese release, hidden behind the Tamagotchi unit. They are described in more detail in the Tamagotchi Research Report Book, and have not been seen or mentioned since.
According to Professor Banzo, they are characters that exist in comics that Tamagotchis read, originating from a hostile world known as the "Iyatchi Planet" (いやっち星). However, they are also seen hidden throughout Tamagotchi Town within the Research Report, suggesting they may be real. They resemble normal Tamagotchi characters, except they have exaggerated details, sharp teeth, and crazed expressions. They are often seen carrying dangerous objects, such as knives, axes, and chainsaws, which frighten other Tamagotchis.
Their name comes from the Japanese word "iya" (嫌), meaning unpleasant or detestable. Their designs bear a striking resemblance to early Digimon artwork.
Gaiatchi (ガイアっち) refers to all living Tamagotchi that are part of the natural ecosystem. They have been visible since Tamagotchi was introduced, but the name for this subspecies wasn't mentioned until Tamagotchi 'Round The World. This term can refer to things like plants, trees, and clouds, but can also refer to planets and celestial bodies, such as Sunnytchi, Blackholetchi, or even the Tamagotchi Planet itself.
Gaiatchi have not been able to be raised on any virtual pet. However, they can be cared for in Tamagotchi 'Round The World.
Hanerutchi (はねるっち) characters are characters based on characters and skits from the Japanese TV show "Haneru No Tobira". They reside in Hanerutchi Town. Hanerutchi characters resemble humans, although they still have "-tchi" on the end of their names and are capable of Evolution, whereas other human characters are not. They resemble cartoon-like humans in artwork or when performing a Close Up, but otherwise resemble heads with legs as sprites, similar to Oyajitchi.
Hanerutchi characters are generally separated from standard Tamagotchis, they do not come into contact with each other although they have a similar lifestyle, except that their place of residence replaces all words and names of areas involving "Tamagotchi" with "Hanerutchi".