Apistogramma Identification, Classification, and Naming

Apistogramma are beautiful tropical fish that are highly prized by many hobbyists. As of 2023, there may be as many as 500 identified Apistogramma species, types, or forms, and more are discovered every year. This makes it almost impossible for anyone to keep up with but, there are a few hobbyists in the world who dedicate their time to uncovering and classifying new fish.

Introduction to Apistogramma

While there is a lot of diversity between Apistogramma species, they all share some common characteristics. Chief among these is their small adult size. In the aquarium, the largest Apistogrammas might reach 3 inches in length (or slightly larger depending on the species). However, it is very rare to find an Apistogramma in the wild that approaches that length.

With few, if any exceptions, Apistogramma males are larger and more colorful than females, and often the difference can be dramatic. Males of many species have elaborate or extended fins. Some have extended dorsal fin spikes arching high above their bodies, some have high sail-like dorsals, and others have regular dorsals of varying heights. The tail, or caudal fin, also shows great variation. From round to spade-shaped to lyretail, Apistogrammas exhibit a great variety of caudal shapes and colors. Many males exhibit long flowing ventral fins. These fins are attached to the lower front part of the body and, in some species, they will grow to great lengths. All of these differences help us to classify the fish.

Female Apistogramma are generally a gray to brown to yellow color when not in breeding colors. During breeding and brood care they will become a shade of yellow which varies greatly between species. Some are a brilliant lemon yellow while others are a much more subtle, almost pastel yellow color. This color difference can be very dramatic in some species of Apistogramma. Generally, the female will be drab-colored when she is in a non-aggressive and non-breeding condition. However, colorless females seem to be a target for aggression and unless they are in a group they often suffer and have to hide.

Under good conditions, females will begin to ripen eggs in preparation for spawning. After egg-laying, females develop the yellow coloration that contrasts with the black markings they exhibit. Female Apistogramma can use their colors and patterns to signal to their fry, a behavior that is very interesting to observe. The location, size, and shape of the black markings on the female is helpful for identification. However, it can be impossible to distinguish females of some closely related species.

These two photos are of the same fish, a female Apistogramma sp. xingu. The top photo shows her in her yellow and black brood dress while the bottom photo shows her in normal coloration. Most Apistogramma females exhibit similar color changes but, in some species, the change is not so dramatic.  

Classifying Apistogramma

I’m not an expert at Apistogramma identification or classification. I’ve kept many species for many years but I usually turn to others for help with identification. While I’ve read every book printed in English about apistos, the best source for reliable and up-to-date information is a series of three articles by Mike Wise that are on Tom Christoffersen’s website. Mike is an international expert on Apistogramma identification who has devoted himself to better understanding the evolution, distribution, and classification of Apistos and he has shared his knowledge through these papers:

A Description of Apistogramma Species-Groups

Apistogramma Species List By Species-Groups/Complexes

Paleogeography of South America and Its Effects on the Distribution & Phylogeny of Apistogramma Species Groups

If you are really interested in understanding how Apistos are classified you need to read Mike’s work. This subject is fascinatingly complex and my brief summary here barely touches the surface.

Apistogrammas have inhabited much of South America for as long as 25 million years. They’ve evolved in diverse habitats resulting in the large number of species and forms we are trying to understand today. This makes identifying Apistogrammas an often daunting task. I am not an expert on Apistogramma identification and I do not intend this site to be a primary identification resource as this information is available elsewhere. However, I would like to offer a little background on how the Apistogrammas are classified.

Lineage, Group, Complex, Subcomplex

Apistogramma species are organized into these groupings and subgroupings that share common characteristics to aid in identification. Lineage – Group – Complex – Subcomplex.

• Lineage – Lineage is the broadest classification within the genus. The most recent work indicates that there are a total of four Apistogramma lineages within which all species are found.
• Group – Each lineage has a number of species groups. Some Groups have just a single species while others contain dozens.
• Complex – Within a Group, there may be clearly identifiable subunits of species. These are called a Complex.
• Subcomplex – Within a Complex there are sometimes one or more distinct species groupings that show enough variety that they are placed in a subcomplex.

For years Apistogramma enthusiasts have placed similar species together into functional groups. This has been an elastic process with disagreements about placements and methods but general acceptance of groupings. In recent years genetic studies have confirmed some of the long-held groupings and instituted uncertainty about others. However, as it is unlikely that we will ever achieve a universally accepted standard, here are the major groups summarized from A Description of Apistogramma Species-Groups by Mike Wise.

Apistogramma Species Groupings

Lineage 1
A. regani Lineage
A. regani Group
A. kullanderi Complex
A.-sp. “Xingu” Complex
A. caetei Complex
A. resticulosa Complex
A. commbrae Complex
Apistogrammoides
A. borellii Complex
A. regani Complex
A. sp. “Angle-patch” Complex
A. eunotus Complex
A. eunotus Subcomplex
A. cruzi Subcomplex
A. ortegai Subcomplex
A. alacrina Group
A. alacrina Complex
A. sp. “Mitu” Complex
A. macmasteri Group
A. hongsloi Complex
A. macmasteri Complex
A. macmasteri Subcomplex
A. hoignei Subcomplex

Lineage 1

Lineage 2
A. pertensis Lineage
A. steindachneri Group
         A. pertensis Group
              A. pertensis Complex
            A. velifera Complex
A. iniridae Group

Lineage 2

Lineage 3
A. trifasciata Lineage
A. trifasciata Sublineage
A. brevis Group
A. sp. “D10”-Group
A. cacatuoides Group
A. nijsseni Group
A. norberti Group
A. atahualpa Group
A. atahualpa Complex
A. barlowi Complex
A. trifasciata Group
A. agassizii Sublineage
A. gibbiceps Group
A. bitaeniata Group
A. paucisquamis Complex
A. bitaeniata Complex
A. agassizii Group
A. pulchra Complex
A. agassizii Complex
A. agassizii Subcomplex
A. agassizii
Broad Black Caudal Seam
Subcomplex
A. agassizii Netz
Net-Subcomplex

Lineage 3

How Do Apistogramma Get Their Names

The best names are those for fish that have been formally described. They will have a scientifically assigned genus and species name. While these names are occasionally changed, they are recognized as official. There are currently less than 100 species that are formally described.

Many fish are named when they are first introduced into the hobby. This can be from a private collector or a fish wholesaler who imports them. These names often reference a notable feature of the fish, someone’s name, or a geographic area. Depending on various factors these fish are given an Apistogramma name using one or more of these designations:

• A. sp. is used for a potentially new species without noting its similarity to any other species.
• Sp. aff. (short for “species affinis”) indicates a potentially new species that has an affinity to, but is not identical to, a known species.
• Cf. (short for the Latin: confer, “compare with”) also is used for fish with a similarity to another species. However, cf indicates that there is an uncertain relationship.

Apistogramma A Numbers

In 2005, a group of respected German aquarists introduced an Apistogramma naming system that assigned a number to every known species. Using photos of almost every form of Apistogramma ever imported into Germany and information from a global network of contacts they were able to assign numbers to 243 species (A1 to A243). Each A number identifies a unique species form or variety of Apistogramma. They published their work in a book titled South American Dwarf Cichlids. This remains the best book available for identifying Apistos.

Unfortunately, the A numbering system is rigid and there is no way to logically expand it to add new discoveries. Consequently, the A numbers are rarely used in the North American hobby. However, when they are available, I list the A numbers of the Apistos that I feature on this website.

Apistogramma D Numbers

New Apistogramma species/forms are discovered all the time. However, it takes many years before a species receives formal naming and most species likely never will. Common names and trade names are often suspect and can be worthless. So what do we do about naming the new discoveries?

Tom Christoffersen is a hobbyist from Norway who has spent more time searching for new Apistos than anyone I’ve known of. Tom has discovered many different species and forms and he felt that there should be some way to “name” new discoveries. Consequently, he started using “D” numbers to name his fish. Each new species or form gets the next D number and Tom publishes the D numbers and some species info on this website. As of April 2023, he’s up to D 62. Tom also publishes info about other new discoveries that are just given trade names.

Apistogramma Common Names

There are generally two types of common names for Apistos, names assigned by a breeder and names assigned to newly discovered fish. When a fish is first discovered, the collectors and exporters give the fish a name of their choosing. Since collecting site information is often a closely held secret, often only one exporter will ever offer the fish, and the common name (or trade name) they give it is widely accepted. While sometimes more than one trade name is given to a fish it’s usually not much of a problem.

On the other hand, common names assigned by breeders can be a major problem. Most breeders want to get the highest price they can for their fish and will often add a colorful-sounding name to a fish that is already well-established. Sometimes there is a valid reason for providing a new name to a new strain but too often new common names add to the confusion surrounding the genus. Be very careful if you are buying fish based on a common name.

How to Identify Your Apistogramma

Most of the information on this page is of little use if you are trying to identify a fish in your aquarium. In most cases, you will have purchased the fish with a name attached to it. A quick search online will show you enough photos that you can usually figure out if that is what you have.

Sometimes you need more assistance and I suggest you turn to the expertise available on the web. The forum at Apistogramma.com will be able to answer any identification question you have. If it’s a common species or a rarity you’ll find experts who can help. Also, there are a couple of excellent Apistogramma groups on Facebook where you can get help.

I’m still a believer in printed books. While the only books available are very dated, they still contain photos, descriptions, and discussions that will provide you with a much better understanding of the genus. To learn more about the books that might be available visit Dwarf Cichlid Information Resources.

Frequently Asked Questions

Essential Articles About Apistogrammas
The Genus Apistogramma
Apistogramma Aquarium Care
Breeding Apistogrammas
Understanding Apistogramma Classification and Identification
Live Plants in the Apistogramma Aquarium
How and Where to Buy Apistogrammas and Other Dwarf Cichlids