The species currently known to science
Today the biological science knows 18 species, which have been recognised through published first descriptions, but many more forms are known, whose status remains completely unclear.
One reason for this is that the scientific discussion about the concept of species is much more complex today. It differs from the earlier concept which is based on the classical taxonomy. For example today it is widely accepted that the continuous progress of evolution ensures that speciation is ongoing everywhere. Thus the existence of many transition stages is possible, or even is the norm. The term “semispecies” is thus well established in modern biology. But in some areas of zoology, including the ichthyology, little use is made of this concept up to now. Even the more traditional concept of a subspecies is rarely used. Anyway wherever hobbyists follow , there will be a significant gap to cutting-edge research.
As the previous descriptions of the licorice gouramis are based exclusively on traditional, phenotype-related working methods, which neither consider genetic characteristics nor fish behaviour, it is unclear if these described 18 species will remain valid or if they have to withstand a subsequent revision of the genus. Both is possible: some of the known species might have to be downgraded to subspecies, while some of the recently discovered local forms might receive this status or even the status of a new species.
Today we know the following species: alfredi, allani, anjunganensis, bintan, deissneri, filamentosus, harveyi, linkei, nagyi, opallios, ornaticauda, pahuensis, paludicola, parvulus, quindecim, rubrimontis, sumatranus and tweediei.
Because of the uncertain relationships and for the ease of access, in the following discussion we arrange today’s accepted species in alphabetical order. This is based on the name of the fish (of course other criteria can be used; you can be informed about this if you click on the link ”other methods of arrangement”).
Each of the species will be introduced here at least with one picture. Links to other pictures in the internet are provided as well. For all species we give brief information about their localities, their natural distribution, the most important external (colour and structure) features for identification, sexual dimorphism and species-typical behaviour. Further information will be provided as needed. The source of the first description will be given as well as a selection of important specialised literature.