opal­lios

Parosphromenus opallios

Kot­te­lat & Ng 20

First descrip­tion:Diag­noses of six new species of Parosphromenus (Teleostei: Osphrone­mi­dae) from Malay Penin­sula and Bor­neo, with notes on other species. The Raf­fles Bul­letin of Zool­ogy 2005 Sup­ple­ment No. 13: 101113.

Char­ac­ter­is­tics: total length max. 3.5 cm. Dor­sal struc­ture: XI-​XIII, 68, total 1819, anal fin: XI-​XII, 1011, total 2123. ♂ in breed­ing colourit often becomes very dark, with vary­ing (depend­ing on the local­ity), usu­ally strik­ing red zones, whitish-​turquoise coloured fin seams, and blue-​colored, spot­ted ven­trals with light blue fil­a­ments, ♀ dis­tinctin­guished, besides the much paler over­all coloura­tion and the lack of bright edges of the uncoloured unpaired fins, espe­cially by the less pointed dor­sal fin, which often appears rounded. The body often appears slightly com­pact. — Vari­a­tions see below.

Sim­i­lar species: for the males mainly pos­si­ble (on first glance) with other par­tially red-​finned species of the bintan-​harveyi group, like rub­ri­mon­tis or alfredi but upon closer inspec­tion well dis­tin­guish­able in full breed­ing con­di­tion by the char­ac­ter­is­tic colour dis­tri­b­u­tion. In females, the fish can cer­tainly be eas­ily con­fused with other species of the bintan-​harvey group.

Occur­rence /​Dis­tri­b­u­tion: Bor­neo: Kali­man­tan Ten­gah, Suka­mara area, river basin of the Jelai Bila, at Kali­mati in the Arut Basin (Lamand region) close to Pangkalan­buun and in the Beni­pah river SW Kubu. Linke mea­sured a con­duc­tiv­ity of 9 micro Siemens /​cm, hard­ness val­ues less than 1 degree KH and GH and a pH slightly below 4.0 in dark brown col­ored water. The fish were found mainly in the heav­ily over­grown shal­low lit­toral zones. The species lives together in some of their habi­tats with linkei. As today a much wider area of dis­tri­b­u­tion is known as it was assumed before (“Suka­mara”), it is pos­si­ble to most likely that dif­fer­ent forms, which partly vary sig­nif­i­cantly regard­ing coloura­tion, indi­cate the pres­ence of vari­ants, whose genetic iden­tity or sep­a­ra­tion is still com­pletely unknown.

Threat: very high, just like many other species, because of rain for­est destruc­tion. This is true espe­cially for the low­land forms and even more, as the vari­a­tion of the species is obvi­ous and indi­cates prob­a­bly an already ongo­ing divi­sion in (also) genet­i­cally sep­a­rated populations.

Discovery/​First import:col­lected for the first time by Kub­ota, Linke et al. in 1990. Prob­a­bly ear­lier, but then not recog­nised as a dis­tinct form. The fish was named “P. spec. of Sukarma” until the first descrip­tion in 2005.

Trade: the species was ini­tially known only from pri­vate imports, but has been traded com­er­cially to a lim­ited extent as well recently.

Care /​Breed­ing: not dif­fer­ent from the stan­dard breed­ing con­di­tions. A a low germ den­si­tiy is very impor­tant, which can be achieved by low pH value (max. 4.5) and the pres­ence of humic sub­stances. Prob­a­bly failed breed­ing attempts go back to pop­u­la­tion dif­fer­ences, but the back­ground is still unknown.

Behav­iour /​Par­tic­u­lar­i­ties:stan­dard cav­ity nesters. The species belongs to the head-​down-​courtshipers. It is strik­ing that the nat­u­rally col­or­ful fish occa­sion­ally lose their intense color in aquar­i­ums, espe­cially after suc­ce­sive gen­er­a­tions. How­ever, most likely, wrong water para­me­ters are the rea­son for this.

Lit­er­atur:

Weblinks:

Biotope of parosphromen­nus opallios

Parosphromenus opallios Copyright KishiParosphromenus opallios / linkei habitat - Sukamara Copyright KishiParosphromenus opallios / linkei habitat - Sukamara Copyright KishiParosphromenus opallios / linkei habitat - Sukamara Copyright Kishi

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