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Parosphromenus deissneri (BLEEKER, 1859)

Deissner's Liquorice Gourami

SynonymsTop ↑

Osphromenus deissneri Bleeker, 1859


Parosphromenus: from the Latin para, meaning ‘beside’, and the old generic name Osphromenus.

deissneri: name for Mr. Deissner, who discovered the species.


Order: Perciformes Family: Osphronemidae


Endemic to the island of Bangka in Bangka-Belitung province, Indonesia. It is known from a number of localities, mostly in the northern and eastern portions of the island, within an overall range measuring approximately 70 km in diameter.

Bleeker’s original type locality is given as ‘Baturussak, Bangka’, and the neotype locality (see ‘Notes’) is ‘Sungai Baturussa basin, 8 kilometers from Pudingbesar on the road to Kampong Simpan, Bangka, Indonesia’


Has been collected among vegetation in jungle swamps and streams containing slowly-moving, tea-coloured water.

In unaltered habitats the dense canopy of branches above means very little light penetrates the surface of such environments, and riparian vegetation also tends to grow thickly.

The water is normally stained with humic acids and other chemicals released by decaying organic materials, the dissolved mineral content generally negligible and pH as low as 3.0 or 4.0.

Unfortunately in some cases it now survives only in remnants of heavily-modified peat swamp habitats such as irrigation ditches and roadside canals.

Habitats described by Linke (2012) consisted of small blackwater streams with pH ranging between 4.72-4.84, electrical conductivity 4-8 μS/cm and water temperature 26.9-27.6°C/80.5-81.7°F. The fish were collected from shallow, marginal areas with depth of 40-100 cm among vegetation, some of which was growing emerse.

Maximum Standard Length

35 – 40 mm.

Aquarium SizeTop ↑

An aquarium with base dimensions of 40 ∗ 20 cm or equivalent is sufficient for a pair.


Can be maintained in a fully-decorated aquarium although many breeders prefer not to use a substrate for ease of maintenance.

Driftwood roots and branches can be used and placed such a way that a few shady spots are formed, and clay plant pots, lengths of piping or even plastic camera-film containers can be included to provide further shelter and potential spawning sites.

The addition of dried leaf litter further emphasises the natural feel and as well as offering additional cover for the fish brings with it the growth of microbe colonies as decomposition occurs. These can provide a valuable secondary food source for fry and the tannins and other chemicals released by the decaying leaves are also considered beneficial for fishes from blackwater environments. Alder cones may also be used for the latter purpose.

All Parosphromenus spp. require acidic conditions with negligible carbonate hardness and very low general hardness so a reverse osmosis unit or other method of obtaining soft water may need to be employed, and this can be further acidified using phosphoric acid or similar if necessary. There is no need to use natural peat, the collection of which is both unsustainable and environmentally-destructive.

Like others in the genus this species does best under fairly dim lighting. You can add aquatic plant species that can survive under such conditions such as MicrosorumTaxiphyllum or Cryptocoryne spp., while floating vegetation, especially Ceratopteris spp., is also useful.

Filtration need not be too strong, with an air-powered sponge filter or similar adequate, and since this species tends to be maintained in pairs (see ‘Behaviour and Compatibility’) a filter may not be required at all provided the fish are not overfed and maintenance is stringent.

The latter must include small weekly water changes of 5-10 % aquarium volume with irregular or larger changes not recommended. It goes without saying that these are fishes are sensitive to fluctuating organic wastes and should never be introduced to biologically-immature aquaria.

Water Conditions

Temperature22 – 28 °C

pH3.0 – 6.5

Hardness18 – 72 ppm


This species is chiefly a micropredator feeding on tiny aquatic invertebrates, therefore in the aquarium it must be offered a variety of small live foods such as Artemia nauplii, DaphniaMoina, mosquito larvae, micro worm, etc.

Frozen foods are sometimes accepted but not considered sufficiently-nutritious, while the majority of dried products are normally refused.

Behaviour and CompatibilityTop ↑

Not recommended for the general community aquarium. Its care requirements, disposition, and especially conservation status dictate that it should be maintained alone or alongside a group of small, peaceful cyprinids such as Boraras or Sundadanio spp.

Likewise, different Parosphromenus spp. should not be kept together since the females can be difficult to tell apart, and some are undoubtedly capable of hybridising.

A mixed-gender group can be maintained if you wish, although most breeders prefer to maintain sexed pairs since some fry may survive alongside their parents but not usually if other adults are present.

Sexual Dimorphism

In males the dorsal, anal and caudal fins have a thin whitish to bluish margin with a black subdistal band bordered internally by a series of bluish oval-shaped markings. The proximal portion of these fins is black to reddish, and the posterior part of the dorsal sometimes contains a small bluish or greenish iridescent patch. The pelvic fins are iridescent greenish-blue with a white to bluish filamentous tip, while the pectoral fins are hyaline. Nuptial males exhibit an overall more intense colour pattern.

Females are far less colourful and lack the colourful blue and red bands in the dorsal, anal and caudal fins. Both sexes are also capable of rapidly changing colour depending on mood and become significantly darker when aggressive, for example.


Normally spawns in small caves or among leaf litter and forms temporary pair bonds with the male solely responsible for egg and brood-care.

Parosphromenus spp. have been grouped arbitrarily based on courtship behaviour in males which adopt a ‘head-down’, ‘head-up’, or ‘horizontal’ position depending on species.

P. deissneri sometimes displays the former posture in which the male assumes a near-vertical position with the head lowermost and fins splayed during nuptial displays but also often adopts a more horizontal shape.

Sexually-active males form small territories at the centre of which is a small cave normally formed from leaf litter in nature, although in aquaria any suitable structure may be chosen (see ‘Maintenance’).

They then attempt to attract females in the vicinity to enter the cave via spectacular displays as described above. Eggs and milt are released in batches during a series of embraces in which the male wraps its body around that of the female.

Some males construct a rudimentary bubble nest inside the cave while others do not, but either way both male and female attempt to attach the eggs to the ceiling after they are released. Subsequent spawning embraces may dislodge eggs from the roof of the cave, and inexperienced adults sometimes simply eat them so a degree of patience may be required until the fish get things right.

Following a successful spawn the female leaves the cave and proceeds to defend the surrounding area while the male tends to the brood.

Incubation is normally 24-36 hours with the fry mobile around 4-6 days later. They initially swim without direction and the male will collect and return them to the ‘nest’ but after 3-5 additional days are fully free-swimming and leave the cave at which point parental care ceases. They may require Paramecium, rotifers or similar as a first food but are quickly able to accept Artemia nauplii and suchlike.

If the aquarium is well-structured fry can often be raised alongside the parents, but in more basic set-ups should be removed and grown on elsewhere.

NotesTop ↑

P. deissneri was the only recognised member of the genus for almost a century following its description in 1859.

As a result its name has and continues to be widely misapplied in both aquarium and ichthyological literature although it’s probably always been very rare in the hobby, while a number of fishes previously identified under the name from other parts of Southeast Asia have already been described to science.

A redescription was published by Kottelat and Ng (1998), and they took the unusual step of requesting the assignation of a neotype. This was necessary because during their investigations the authors discovered the existence of two Parosphromenus species on Bangka Island, and Bleeker’s original description was based on a single female specimen which was in very poor condition therefore could not confidently be assigned to either taxon.

In addition, Parosphromenus spp. are typically identified by male colour pattern, with females tricky to tell apart.

The original type locality of P. deissneri is ‘Baturussak’ and there is a river named the ‘Baturussa’ which drains Bangka’s eastern coast from which fresh Parosphromenus material had been obtained, therefore the authors concluded that eastern populations were most likely to represent Bleeker’s P. deissneri.

Those from the south and west of the island differed in caudal-fin shape and were described as new species P. bintan, so named since it also occurs further north on Bintan Island, Riau Islands province, Indonesia.

P. deissneri can be told apart from all congeners by following combination of characters: pale subdistal bands in the unpaired fins of males comprising a series of oval spots located on the fin membranes with dark rays between; median caudal-fin ray not branched and in adult male prolonged into a filament; 12-13 spinous and 6 soft dorsal-fin rays; 12-13 spinous and 8-11 soft anal-fin rays; 11-13 pectoral-fin rays.

Aquarists often refer to Parosphromenus spp. collectively as ‘liquorice/licorice gouramis’ or ‘paros’.

The genus occurs in southern (peninsular) Thailand, Peninsular Malaysia, Sumatra (Indonesia, including the islands of Bintan, Bangka and the Riau Archipelago), and Borneo (Malaysia and Indonesia). All members are small-growing inhabitants of freshwater swamps and associated streams, and the grouping was considered to be monotypic, containing only P. deissneri (Bleeker, 1859), for almost a century. Additional taxa have been described on a sporadic basis since the 1950s and there currently exist 20 recognised members with more likely to follow.

Despite the generic name the results of phylogenetic analyses by Rüber et al. (2006) suggest that Parosphromenus is most closely-related to Betta or Trichopsis in an evolutionary sense. All three of these are sometimes included in the putative subfamily Macropodusinae alongside Macropodus, Pseudosphromenus and Malpulutta.

Like others in the suborder Anabantoidei this species possesses an accessory breathing organ known as the labyrinth, which permits the fish to breathe atmospheric air to a certain extent. Comprising paired suprabranchial organs formed via expansion of the epibranchial (upper) section of the first gill arch and housed in a chamber above the gills, it contains many highly-vascularised, folded flaps of skin which function as a large respiratory surface. Its structure varies in complexity between species, tending to be more developed in those inhabiting harsher environments. While some labyrinth fishes can be observed taking regular gulps of air from the surface others, including Parosphromenus spp., do so less often.


  1. Bleeker, P., 1859 - Natuurkundig Tijdschrift voor Nederlandsch Indië v. 18: 359-378
    Negende bijdrage tot de kennis der vischfauna van Banka.
  2. Finke, P. (ed.) - World Wide Web electronic publication, http://www.parosphromenus-project.org: Accessed on 13.02.10
    The Parosphromenus Project.
  3. Kottelat, M., 2013 - Raffles Bulletin of Zoology Supplement 27: 1-663
    The fishes of the inland waters of southeast Asia: a catalogue and core bibiography of the fishes known to occur in freshwaters, mangroves and estuaries.
  4. Kottelat, M. and P. K. L. Ng, 2005 - Raffles Bulletin of Zoology Supplement 13: 101-113
    Diagnoses of six new species of Parosphromenus (Teleostei: Osphronemidae) from Malay Peninsula and Borneo, with notes on other species.
  5. Kottelat, M. and P. K. L. Ng, 1998 - Ichthyological Exploration of Freshwaters 8(3): 263-272
    Parosphromenus bintan, a new osphronemid fish from Bintan and Bangka islands, Indonesia, with redescription of P. deissneri.
  6. Linke, H., 2012 - Amazonas Sep/Oct 2012: 29-34
    Traveling in Licorice Gourami biotopes.
  7. Rüber L., R. Britz and R. Zardoya, 2006 - Systematic Biology 55(3): 374-397
    Molecular phylogenetics and evolutionary diversification of labyrinth fishes (Perciformes: Anabantoidei).
  8. Schindler, I. and H. Linke, 2012 - Vertebrate Zoology 62(3): 399-406
    Two new species of the genus Parosphomenus (Teleostei: Osphonemidae) from Sumatra.

27 Responses to “Parosphromenus deissneri – Deissner’s Liquorice Gourami (Osphromenus deissneri)”

  • Sverting

    It would be nice to add, that although GH can be as high as 8, the 0 dh KH is a must.

  • oaken

    That’s very exaggerated Sverting. I’ve kept deissneri (the real one, for the record) and several other Parosphromenus species for years in water that measures 3 dkH and 3-4 GH. Most species also breed perfectly well in such water.

  • Sverting

    It’s not exaggarated if you want to breed them. In case of the Parosphromenus the absence of calcium is crucial. Otherwise the eggs might not stick to the ceilling of the chosen grotto.

    Also the “little or no water movement” isn’t really correct. Deissneri live in the regular streams, the absence of water movement isn’t their prefered way of living.

    The keeping in pairs section is only correct in case of the intensive breeding. Otherwise it’s good to keep them in groups, becouse of the interesting social behaviour. If you dont want to breed them, get them some company!

    To the dark substrate.. Not really imprtant. The better way is to put a big bag of dry leafs into the water. In case of some specimens leafs are even prefered over grottos.

    In the article should also be a note stating, that there are 20 Parosphromenus species, and it is easy to make mistakes. Most of the Parosphromenus imoprted are listed as deissneri, but infact only a small percentage are actually the P. deissneri. The fish can live long – up to ten years. It becomes fertile at the age of two. It’s also endangered. The association caring for them is called the Parosphromenus Project.

  • Hi Sverting yep agree with most of what you say. I’ve got photos of most Parosphromenus species, and many of their habitats, ready and waiting to add to the database, have read the relevant scientific literature and am aware of the Parosphromenus Project and their great work.

    This is just another of those species, and indeed genera, I’ve not had time to add/edit yet. Currently busy with other things but will get around to it eventually!

    Gustav, did you breed P. deissneri under those conditions mate?

  • Yuk, just spotted that we didn’t even have a photo. Added one of yours Gustav. 🙂

  • Sverting

    Well… that is no deissneri xD This is a blue line or bintan! Deissneri has a filament at the dorsal fin!

  • Sverting

    For reference:

    bintan: http://parosphromenus-project.org/en/p-bintan.html

    deissneri: http://parosphromenus-project.org/en/p-deissneri.html

  • Thanks Sverting and yes, I see. In that case we don’t have an image of this species so think I’ll take the profile offline for the time being.

    Will leave it up for 12 hours or so to give you both a chance to read this then pulling it.

  • Sverting

    I can ask dr Finke for the rights to the photo. I am sure, that if there were links to the Parosphromenus Project in the description, than he would be more than happy to provide them.

  • That would be great. Thanks!

  • oaken

    Since my comment disappeared I’m reposting it upon request:

    Sverting, yes that is a Parosphromenus deissneri. My fish were F1 specimens that came from deissneri collected by Thor Dahl and Horst Linke in 2008. Then bred by Karsten Keibel. However the next generation did not develop the filament in the caudal fin like the wild fish had.

    Personally I’ve bred P. parvulus, P. sp. “Sungai Bertam”, P. nagyi and P. sp. “Blue Line” with such water. I also have a friend that bred P. ornaticauda in similar water (that is, not RO-water but water with similar values to mine). And with this being said P. ornaticauda and P. parvulus are probably two of the harder species to breed.

  • Sverting

    The description of bintan:

    ” Kottelat and Ng redefined the species P. deissneri in the same publication, so P. bintan can not be confused anymore due to the significant structural differences and color differences of both types. In males, the risk of confusion with other licorice gouramis is low, because of the color differences in the phenotypic differentiation of described round-tail-Parosphromenus.”

    And for the deissneri:

    “♂ in nuptial plumage structurally well identifiable by the triangular, up to one centimeter long black caudal filament.”

    So no filament – no deissneri.

    I;m trying to ask for permission the author of some deissneri photos. I’ll give some updates on that.

  • Sverting – that clearly states NUPTIAL plumage, which suggests the filament is a temporary growth in breeding individuals.

    The fish in the pic is an F1 offpsring of wild P. dessneri collected by Linke and Dahl as Gustav says above.

  • P.S. does anyone have a copy of the bintan paper? You’ve inspired me to update these profiles. 🙂

  • Sverting

    I suggest to ask people on Parosphromenus project. They will be glad to help. If you’re interested in Parosphromenus sp. “Blue Line” page, than I have an awfull lot of photos of my young ones, and I know a person that has really good shots of adults.


    Maybe dr Finke has some copies,hat he would agree to share? You should probably make an official request.

  • Some photos would be really useful, I’ll send you an email. Thanks again.

  • Sverting

    So I asked dr Finke, and these are the most important parts. If allowed, I will post the whole e-mail.

    I can well imagine one could think it’s a P. deissneri, but equally one could think it is not.[…]

    The fish shown exhibits some features typical for a deissneri-male:

    1 The dorsal fin is rather long
    2 The pattern of blue markings especially in the caudal resembles to some extent deissneri
    3 The same holds to a lesser extent for the dorsal
    4 And to a still lesser extent for the anal fin.

    But there are some important characteristics of a male deissneri missing:

    1 There is no black filament at the end of the caudal
    2 The caudal is rounded, whereas that of deissneri has a rhombic from
    3 The length of the dorsal is not enough for deissneri
    4 The markings I spoke of in caudal, dorsal and anal are not of the typical deissneri-character (short parallel streaks with clear black intervals between each). Even in the most similar fin, the caudal, they do not show that streaky form and they are not directed strictly parallel and horizontally.


    It is clearly no deissneri.[…]
    At any rate this picture does not show a deissneri. So, it should be removed from the page that tries to explain that species. There are enough perfect pictures of that species. And I appreciate the written text very much: it is well-founded with one exception: Several times only one location is named again and again. There are quite a many locations where deissneri was found and still is found.[…]

  • oaken

    I would be interested to hear what Dr. Finke had to say about the origin of the fish. Or did you leave that out?

  • Sverting

    Ok. Since the server is finally up, now is the time for the whole e-mail.

    Sverting, yes, this is quite an extraordinary fish. I can well imagine one could think it’s a P. deissneri, but equally one could think it is not. I shall explain my opinion: It is no deissneri and should be deleted from a homepage trying to explain that species.

    The fish shown exhibits some features typical for a deissneri-male:

    – The dorsal fin is rather long
    – The pattern of blue markings especially in the caudal resembles to some extent deissneri
    – The same holds to a lesser extent for the dorsal
    – And to a still lesser extent for the anal fin.

    But there are some important characteristics of a male deissneri missing:

    – There is no black filament at the end of the caudal
    – The caudal is rounded, whereas that of deissneri has a rhombic from
    – The length of the dorsal is not enough for deissneri
    – The markings I spoke of in caudal, dorsal and anal are not of the typical deissneri-character (short parallel streaks with clear black intervals between each). Even in the most similar fin, the caudal, they do not show that streaky form and they are not directed strictly parallel and horizontally.

    So, what is this fish?

    It is clearly no deissneri. All deissneri we know (I have seen many from diverse origins: wild caught one by K. Bieler, G. Kopic, A. Brown, offspring bred by these and by K. Keibel, B. Wilden, B. Bussler, and my own) do not show any marked variation. The pattern of specific fin structure and markings is remarkable stabile. P. deissneri has one of the longest dorsals of the genus (XII-XIII, 6); in fact the male deissneri appear to be rather longly drawn in general. And there was always that typical pattern of well-isolated and parallel blue streaks in all unpaired fins, and the rhombic from of the caudal with a black filament of several millimeters.

    P. deissneri is one of the easiest species to determine. There are very good photos of it, especially those of Keibel or Linke. Take the cover-picture of the Parosphromenus-AMAZON-issue, showing one quindecim and two times deissneri.

    Nevertheless the picture is disturbing. Which licorice gourami does it show to us? I do not know. It’s a bintan-type with its rounded caudal, but I cannot say it to be typical for the one or the other. What disturbs me most is the statement you cite that this fish is an offspring of a clearly determined deissneri. So I infer from that: This fish shown here in not wild-caught. Its an aquarium breed.

    Would it be wildcaught, I should say: Well, it’s new to us, or: It’s a natural hybrid, or: It’s deformed by immissions into his natural habitat. We have very bad reports of immission of old dirty tin mines into the blackwaters of Bangka (Yashuyuki Kishi from the “Team Borneo”). But apart from my conclusion on the basis of your citation that the fish must be aquarium bred it is very unlikely that so many clear markers of deissneri would be affected simultaneously as it is the case with this fish. That it should be new to us would be possible (if it is wildcaught), and that it is a natural hybrid, too. But both is not very likely.

    One interpretation I have is that it is an aquarium bred hybrid including a deissneri as ancestor. This is possible, of course, although we have little proof of it. The female deissneris could more easily be interchanged than the males. The other interpretation is that it is an unknown bintan-type (P. cf. bintan) that shows a bit more variation than we see normally. We know that P. bintan occurs on Bangka, too.

    At any rate this picture does not show a deissneri. So, it should be removed from the page that tries to explain that species. There are enough perfect pictures of that species. And I appreciate the written text very much: it is well-founded with one exception: Several times only one location is named again and again. There are quite a many locations where deissneri was found and still is found. Three members of our project will travel to that island in autumn this year to look for the real deissneri.

    Univ.-Prof. em. Dr. Dr. h.c. Peter Finke

    Theory of Science and Cultural Ecology (Bielefeld University)

  • Hi Sverting, you didn’t answer Oaken’s question? I too would like to know!

    I’ve edited the locality details as per Dr. Finke’s email, very kind of him to reply in such detail. 🙂

  • Sverting

    The fish parents, or further ancestor, might have originated from the import from Bintan. There are two populations living closely of P. bitan and P. dessneri. Females were probably confused, and since Parosphromenus are easily crossbred, now we have the offspring in the following form. I asked him about that in the following way:

    “I thought that it might be a hybrid between deissneri and bintan. Probably achieved at the early stage, when these two were thought to be one an the same. Maybe deissneri male and bintan female?”

    and the answer was:

    “Possibly a hybrid of a male deissneri (which is easy to be recognized) and a female cf. bintan (which could more easily be interchanged with a female deissneri).
    But surely not at the early days already. The differentiation is known since more than a decade. But the females are different, it is sure, but not as different as the males. For me, this is the most likely hypothesis.
    At any rate, we should store that picture. We need pictures of hybrids. Although we are not sure in this case, it’s a serious possibility. And the picture would iluustrate that quite impressively.
    What do the makers of “Seriously fish” say?”

  • Ok thanks Sverting, I’ve been meaning to write to Dr. Finke anyway and this seems a suitable time to do so. Gustav, will mail you first.

  • heleneschoubye

    I have been reading through this discussion about Oakens photo, and I think I have to join in the discussion now 🙂
    I am from Denmark, and I have had offspring of the same fish as Oaken is describing – the wild caught deissneri which Karsten Keibel recieved from Norway and then bred. I was also present when these fish was ‘discovered’ in a tank in Norway, – and I know for a fact that there were were two species mixed up in the same tank – some which looked certain ‘deissneri’ and some which were another species, said to come from Bangka – and possibly looking like a bintan.
    Unfortunately i have no contact with Karsten Keibel anymore – and do not think he is into fish keeping any more, so theres no way to ask him. But I have a danish forum-thread in which these fish are discussed, and I can at least verify that there could be some risk that there might have been a crossbreeding occurring. It might not, – I do think Karsten was able to determine a safe male, and a safe female (by the pointed caudal fin) – but if he had other offspring from these fish or if they indeed had bred before he got them .. I wouldn’t be sure.

  • oaken

    Thanks for your comment Helene. I had not heard the part about the fish being in the same tank before. The only thing Karsten told me was that Thor Dahl and Horst Linke caught two species on Bangka in 2008: Parosphromenus deissneri and a species Karsten called Parosphromenus sp. “Bangka Red”. P. sp. “Bangka Red” supposedly looked very different from the P. deissneri that they had caught – especially in the body shapes. He mentioned that the females of the two species were also different (but he didn’t say how). I only have a female left from the fish I got from Karsten in 2009 and I believe they were from the first brood.

  • heleneschoubye

    I quess he felt confident he was able to seperate the fish, – and of course he is the one who could say excatly what happened, but I did find an old forum thread which delt with the discovery of these fish in Norway, and how they got to Denmark, – this is why I remembered it 🙂 .. and there is room for quite some uncertainty as to whether or not there was some mixing, either before or in the journey. I am sure Karsten did not mix them, and I am sure he felt he was able to see the difference, – but …. well, – this discussion regarding the fish in the photo made me think ..

  • I’ve removed the photo now, but should it still be included here as a potential hybrid?

  • heleneschoubye

    I dont know if its the right place to put this photo necessarily – its really not very often one would come across such an exsample, and I quess its not ‘unique’ to p.deissneri.
    But I think its really interesting and worth while to have a record of the particular photo (with the corresponding history) – so as to learn about ‘potential hybrids’.
    We should definitely keep some dokumentation regarding it, I think, – somewhere 🙂

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