Gold barb, also called Schuberti barb, is not a natural wild form.

Gold barb is a popular "gold" colored breeding variant.

Adult gold barb males at times partially become more greenish metallic colored, locally on the upper-middle sides of their bodies, and simultaneously become more red on the sides of their bellies. This becomes especially noticeable when they are eager to spawn.

Adult males are usually a bit slimmer than adult females and their maximum size is a bit smaller than fully grown females. Adult females that are full of eggs and ready to spawn can get much thicker bellies.

Normal standard length (not including the tail fin), for adults that are about one or two year old, is usually about 5-6 cm for males and about 6-8 cm for females. In normal situations that is about as big as they get. However, if kept in excellent conditions from young (for example in big ponds filled with plenty of live food and good water quality) some specimens may occasionally grow to reach twice that standard length, after they are fully grown.

The gold color is a xanthic (xanthoric) color morph.

This is also called xanthochromism, xanthochroism or xanthism. Xanthic color morphs still have some color pigments left, including yellow pigments, but have lost one or more specific color pigments that would otherwise normally be expected, if it was a natural wild color form. Xanthic color morphs have not lost as much color pigments as a pure albino. One or more specific color pigment may possibly also have been replaced by yellow or yellow related pigments, making the organism appear even more vibrant regarding yellow and/or orange and/or red etc. There are many variations of xanthic color morphs in animals. Some xanthic animals have black pupils in their eyes, while some others have red pupils in their eyes. The classic gold barb has black pupils in their eyes, like the two gold barbs in my photo. The vibrant red coloration of most of their fins develops with age in the classic gold barb. Fry and juveniles look a bit different from adults.

A xanthic color morph should not be confused with an axanthic color morph. Axanthic color morphs have lost, or replaced, either yellow and/or red coloration, but retained some, or all, other pigments.

In the aquarium trade there are also several more breeding varieties of "gold barb", such as the yellow variety (with a pale yellow body color and yellow fins) and the "Tri-Colour" variety, but globally they are not as popular as the classic gold barb.

Barbodes is a genus in the subfamily Barbinae in the family Cyprinidae.

• The family Cyprinidae, aka cyprinid fish, is often also called the carp or minnow family.
  
  
• The subfamily Barbinae, and all the genera (plural form of genus) historically included in it, are considered incertae sedis. This means that the taxonomy for this group has not been entirely worked out. Some genera temporary put in this subfamily may or may not actually belong to the subfamily Barbinae. In the future, as researchers make progress, some genera are expected to be allowed to stay in this subfamily, while others may be moved. Genera may also be added to this subfamiliy from any other closely related subfamily. Genera with new names may also be suggested, if a need is discovered, such as when splitting a genus into two or more genera.
  
  
• Barbodes is a genus of small to medium-sized cyprinid fish native to tropical Asia. Some species in this genus may need to be moved in the future. Some newly described or moved species may also get added. Some species in this genus have recently become considered to be extinct. (Species that are endemic to small geographical places are especially vulnerable, to humans impacting their environment directly or indirectly.)

Gold barb is speculated, but not proven, to be a variant of Barbodes semifasciolatus.

Barbodes semifasciolatus is a species said to mainly originate from south west China. There have also been reports of populations in Vietnam, Laos and Thailand. This species is also reported in Russia, but it is unclear if it native or feral. Feral populations are reported in Singapore and Hawaii.

This species is often commonly called chinese barb, or similar generic names. These names often create confusion and mixups, confounding many hobbyists, businessmen and scientists. Barbodes semifasciolatus is often confused with other species. Sometimes it is because they have similar trade names, or similar local names, or maybe China listed as an origin country. Sometimes it is because of (more or less) similar appearenace to other species from Asia. Sometimes it is because of incorrectly pictures or other identification sources used as reference. Often it is a combination of several factors that together adds up to a mixup.

Barbodes semifasciolatus is claimed to have been spread out to many other places by humans, but some of those claims may possiby also (sometimes) be other species, because of mixups and the uncertain situation. The scientiffic name of Barbodes semifasciolatus has also been changed several times, as research has progressed.

There is a possibility that some populations of fishes in the wild (native or feral) that are currently grouped as local variations of Barbodes semifasciolatus may, or may not, be other species, or maybe subspecies, or hybrids.

The actual scientiffic origin of the gold barb is still unclear.

There is a possibility, and in my opinion good chance, that the gold barb may originate from an other species. A likely candidate, in my opinion, is Barbodes snyderi (Snyder's barb, synonym: Puntius snyderi), that can be found in the wild in Thailand and traditionally considered to be endemic to Thailand. However, some speculations have been made if populations of Barbodes snyderi may, or may not, also be found in neighbouring countries and/or a part of China. It is still up for debate and further research and need for proof, to see if those populations are Barbodes snyderi or Barbodes semifasciolatus or something else.

Barbodes snyderi is very closely related to Barbodes semifasciolatus and they are often mistaken for eachother in the aquarium trade. They are almost the same and share a common origin, but they seem to have diverged slightly during evolution in nature. There is also a possibility that the gold barb may originate from cross hybridization between these closely related species, or other species, or a cross between fishes originating from different populations within a species. Most likely there are now several different breeding strains in the aquarium trade that are not the same as eachother in this regard. Everything doesn't stay the same over time in the aquarium trade, compared to when the gold barb was first introduced to the hobby.

When it comes to similar fish/fishes with geographically divided (or geographically spread out) natural habitats in the wild, it is often difficult to draw a clear line where (or if) it becomes different species, compared to local population variations. Humans have also been moving around fishes for thousands of years, but it has escalated recently, as transpotation technology and fishkeeping has progressed. Because of humans, many fishes have found themselves in new places in the wild, either deliberately, accidentally or through carelessness by humans. If they survive and reproduce they may either integrate and/or infest the local ecological systems. Sometimes they breed with local populations of fish.

Whatever the original species and their natural habitas were, might have already become muddled and unclear, without a time machine to go back and investigate. However, as science and gene research make progress, the taxonomy is continiously being revised. There might still be hope of tracing the origin. At the same time many breeders continue to cross species and varieties, sometimes even using genetic engineering with gene modification, in attempts to create new sensational bestsellers. Such attempts usually fail many times, over and over, but sometimes there are exceptions.

Synonyms for Barbodes semifasciolatus:

Barbus semifasciolatus, Capoeta semifasciolata, Puntius semifasciolata, Puntius semifasciolatus, Barbus aureus and Barbus hainani.

Sometimes gold barb may have been called these synonyms, sometimes also with an ending such as [var. schuberti], or something similar, to the name. It is a reference to Thomas Schubert, the American who was involved in the "discovery" or "creation" of the gold barb, aka Schuberti barb.

A "subspecies" that has been up for debate, but not accepted as a subspecies by everyone, is called goldfinned barb and rumored to come from Singapore. It is sometimes called Barbodes semifasciolatus sachsii and other sources may call it Puntius sachsii and/or the synonym Barbus sachsii. It is still unclear to me what this fish is, if it is one or more species, or if it is a native species in Singapore or not. Perhaps it might originate from the aquarium trade. It is unclear to me if there are any long time established feral or native populations in the wild in Singapore. There seems to be several kinds of mixups going on, but sometimes gold barb is sold with this name as a reference. Sometimes this fish may also in some countries be called some of the popular names, as other candidates, for being a natural form of gold barb.

Unfortunately gold barb may sometimes be referred to as golden barb.

Be aware that golden barb is also one of the commonly used popular names of an other completely different species, that is not that closely related and looks quite different. The scientiffic name of that golden barb is Pethia gelius.

Pethia gelius has several synonyms: Cyprinus gelius, Barbus gelius, Puntius gelius, Systomus gelius, Cyprinus canius (misapplied) and Puntius carletoni (misapplied).

Pethia gelius has several popular names: Golden barb, golden dwarf barb, dwarf barb and glass barb etc.

A few more names, of other species of barbs, that sometimes also can cause mixups:

• Golden bumblebee barb Acrossocheilus longipinnis.
  
  
• Goldfoil barbs (xanhtic/yellow/gold/golden version of tinfoil barb) Barbonymus schwanenfeldii.

All written sources related to gold barb, have varying degrees of mixups going on.

The name confusion is widely spread. It is on websites, books, stocklists and so on. The confusion is regarding popular names (names in English, Chinese and other languages) for gold barb and potential scientiffic name(s) and wild form(s) and pictures showing fishes that may, or may not, be whatever the notations claim them to be.

Sometimes the colored up males may be noted as different species compared to not colored up males and females. Sometimes juveniles may be noted as different species. Sometimes juveniles of other genera are misidentified as Barbodes. Sometimes pictures of the same fish are used in several different articles, with different claims on what species it is.

Hopefully, in the future, scientist and devoted barb keepers might bring better order to the situation. Progress regarding information sharing, with digital pictures on the internet and improvement in search engines and databses might help, but might also add more confusion. For now it seems gold barb enthusiasts will have to keep moving on in partial ignorance.

Happy gold barb keeping!