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Gastromyzon spp.

Home Forums Fresh and Brackish Water Fishes Gastromyzon spp.

This topic contains 27 replies, has 7 voices, and was last updated by  Menu 5 years, 10 months ago.

Viewing 15 posts - 1 through 15 (of 41 total)
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  • #300639

    Matt
    Keymaster

    Is there any way to sex them?

    #317265

    Mark Duffill
    Participant

    Taken from “Borneo Suckers”

    Gastromyzon borneensis
    Sexually mature males had heavy tuberculation on postero-ventral part of body slightly larger and more tuberculate secondry rostrum.

    Gastromyzon punctulatus
    Mature fishes of both sexes had small tubercles on dorsal surfaces on head and pectoral fins, tubercules largest and most dense on tip of snout.

    Gastromyzon fasciatus
    Mature fishes of both sexes had small tubercles on dorsal surfaces of head pectoral fins, and sometimes on and anterior rays of pelvic fins, males have dense pathces of small tubercles on dorsal surface of anterior most pectoral fin rays.

    Gastromyzon contractus
    Males have dense patches of small conical tubicles on dorsal surface of anterior most pectoral rays.

    Gastromyzon megalepis
    Males have dense patches of small conical tubicles on dorsal surface of anterior most pectoral rays.

    Gastromyzon ctenocephalus
    Male holotype has dense patches of small conical tubicles on dorsal surface of anterior most pectoral fin rays, as well as ctenoid tubicles, on dorso lateral part of head and on pectoral fin base. The female specimens lack ctenoid tubercles and dense patches of small tubercles on pectoral fin; but have numerous small conical tubercles widely scattered on dorsal surface of head and anterior-most portion of body.

    Gastromyzon danumensis
    Sexually mature males did not have tubercles on postero-ventral part of body, males have larger and longer tuberculated secondary rostrum.

    Other than that females would be slightly larger/plumper than males.

    #317267

    torso
    Participant

    you are right.
    but it’s much easier than that at least with the 7 species I have. females show a “higher/taller” dorsum, they are always larger. and males have that “edge” head-to-pectroral fin, I call it “the-hanger-effect”.
    condition is: a size near the SL. but it works with ctenocephalus, farragus, ocellatus, scitulus, stellatus, viriosus, zebrinus
    may be it’s easier with some pics
    the second picture with cteno shows a pair fighting for dominance. the male is going to loose and is already changing colours back to normal before the end of the fight. females normally are the dominant specimen in adult life.
    the ventral sight shows ocellatus.
    sorry for the disorder. didn’t find the button for changing places.

    Attached files

    #317269

    Matt
    Keymaster

    Very clear in those pics Charles, thanks! Of the ventral shots the top one is female? Interesting you say females are generally dominant as the opposite has been observed in Beaufortia – do they tend to occupy the best feeding spots?

    #317270

    torso
    Participant

    yes a female on the top
    every species is a little diffrerent in temperament: stellatus are of the “smooth” kind. the combination with the best fighters – cteneocephalus – gives very inteersting observations. I have kept them with ocellatus – the most “social” species and now seperately. ocellatus and farragus are very similar, females very large. all in all every genus and species is at least slightly different in behaviour. therefore I don’t keep gastromyzon together with p cheni or sewellia.
    as I feed not on a special spot I can’t judge. but the large specimen just push away smaller ones on the place they are eating at the moment. good to see when tablets are given. they just hold this place by shere presence. gastromyzon species have no problems to share an offered glass with algae on it. sewellia and others do have this problem. seems that the dominance question is then still virulent.
    in nature the constellation is different

    Attached files

    gastromyzonbiotope11.wmv (8.4 MB) 

    #317271

    Matt
    Keymaster

    Ok great, thanks for the info Charles – what do you mean by “smooth”? Peaceful?

    Also have I identified these correctly?

    G. farragus

    G. ocellatus

    But this one is confusing –

    Does G. farragus ever show blue/purple colouration in the caudal fin? All G. ocellatus I’ve seen appear to.

    Attached files

    #317276

    torso
    Participant

    gentle, not rough. gastromyzon are in a way all peaceful and self-conscious
    yes all are right
    about ocellatus/farragus. the spots on the head are supposed to be finer in farragus. but I have some ocellatus with fine spotting. if you look at the pictures it’s interesting to see, that the “classic-pattern-type” with clear lateral “eyes” has a coarser spotting on the head. that’s the type in “borneosucker” too.
    Jim Powers (ocellatus about 8 years old) remarked a washing out of patterns, making it more difficult to distinguish

    #317277

    Matt
    Keymaster

    I’m still confused about these G. ocellatus with blue/violet colouration in the caudal – not a feature mentioned by Dr. Tan. *scratches chin*

    Also is this a juvenile Charles?

    P.S. – We could really do with some pics of G. scitulus if anyone has any.

    Attached files

    #317278

    Mark Duffill
    Participant

    Two G. scitulus pics Matt, I have more and will dig some out later:


    #317279

    Matt
    Keymaster

    Thanks Mark! Does that top fish have blue in the dorsal?

    #317280

    torso
    Participant

    QUOTE (Matt @ Mar 25 2010, 12:23 AM) < {POST_SNAPBACK}>
    I’m still confused about these G. ocellatus with blue/violet colouration in the caudal – not a feature mentioned by Dr. Tan. *scratches chin*

    Also is this a juvenile Charles?

    P.S. – We could really do with some pics of G. scitulus if anyone has any.

    #317281

    Mark Duffill
    Participant

    QUOTE (Matt @ Mar 25 2010, 05:45 PM) < {POST_SNAPBACK}>
    Thanks Mark! Does that top fish have blue in the dorsal?

    A small amount Matt but nothing near as much as ctenocephalus, it was strange as all my other scitulus had no blue at all in the dorsal.

    #317328

    Matt
    Keymaster

    Charles sent a stack of cracking images last night of which most are now uploaded to the relevant profiles. Some really interesting fishes among them including a form of G. scitulus with red distal edges to the caudal fin and these G. zebrinus which look very yellow compared with ones I’d seen previously; the last one almost reminds me of a wee clown panaque. Thanks again Charles!

    Attached files

    #317344

    Matt
    Keymaster

    Any information about this one?

    Attached files

    #318925

    Kajsa12
    Participant

    A few weeks ago I have bought some more G. zebrinus.
    One of them is a bit different and looks exactly like one in this thread.
    Especially the marking and the colour of the caudal fin is different.
    Is this G. zebrinus or maybe some other species?
    (In a few weeks all G. zebrinus will move to their new tank)

    Some pics

    Left the unknown one, at the right new one with ‘normal’ caudal.

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