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Questions on Rhinogobius

Home Forums Fresh and Brackish Water Fishes Questions on Rhinogobius

This topic contains 0 replies, has 1 voice, and was last updated by  mikev 6 years, 2 months ago.

Viewing 15 posts - 16 through 30 (of 122 total)
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  • #349456

    Ferrika
    Participant

    Mike, IF they spawn times, relatively simple. It’s just sometimes quite difficult to persuade them to spawn.
    Although the larvae are free-swimming, but relatively large, and eat from the beginning Artemia nauplii.
    The same applies also for the Rhinogobius nantaiensis. Of which I had from one clutch 150 pups :-)

    Matt, the high proliferation of R. nantaiensis could be one reason why so many animals are caught. Whose populations may be in a place far greater than that of R. candidianus. The catcher collect (unfortunately) often several catches in a container before bringing them to the exporter. And I guess they do not differentiate the animals.

    #349477

    Matt
    Keymaster

    Thanks Jutta. Some unspecified ‘thing’ is still niggling me though. Do you mind if we list it as R. cf. nantaiensis for now?

    Mike if you have more Etheostoma you must get some pics on!

    #349481

    Ferrika
    Participant

    @matt said:
    Do you mind if we list it as R. cf. nantaiensis for now?

     

    For me that’s ok, Matt. I would rather have one cf. too much, as the animals are referred constantly wrong.
    Honestly, most of the identifications at Rhinogobius are only max. 70% sure.

    #349482

    mikev
    Participant

    Thanks, Jutta! I think I’ll try to get them…
    Etheostomas: Matt, will try over the break. The guys I got are these http://www.aquabid.com/uploads/fwusnative1353093364.jpg (not my photo) (Savannah Darter == Etheostoma fricksium; with luck I’ll have another species by the end of the week).

    #349486

    Matt
    Keymaster

    Ferrika said  

    For me that’s ok, Matt. I would rather have one cf. too much, as the animals are referred constantly wrong.
    Honestly, most of the identifications at Rhinogobius are only max. 70% sure.

    Ok great, thanks again Jutta. So, do the nantaiensis always have the spots on the cheeks?

    What a superb-looking fish Mike. 😎

    #349488

    Ferrika
    Participant

    No, not always, Matt. Approximately of 95%.

    #349492

    Matt
    Keymaster

    Ok. :)

    #349512

    mikev
    Participant

    @matt said:

    What a superb-looking fish Mike. 😎

    Thanks Matt! :D

    The 2nd species is Etheostoma thalassinum, Seagreen Darter, got them today (2m/4f). Again not my photo, . Actually it would be difficult for me to match this shot, these are breeding colors; the normal appearance is less intense. The guys I got have green anal fin all right, but not elsewhere.

    The plan is to get at least one more species… that one will not be colorful but likely easier to breed.

    #349516

    Matt
    Keymaster

    This may warrant a thread in its own right…

    #349521

    Matt
    Keymaster

    Questions about breeding R. candidianus – do the fry undergo a pelagic stage, and why is it difficult to induce them to spawn?

    Edit: the profiles are now ready for comments and corrections, too. :)

    http://www.seriouslyfish.com/species/rhinogobius-candidianus/

    http://www.seriouslyfish.com/species/rhinogobius-cf-nantaiensis/

    #349523

    Ferrika
    Participant

    @matt said:
    Questions about breeding R. candidianus – do the fry undergo a pelagic stage, and why is it difficult to induce them to spawn?

    Yes, they go through a pelagic, ie, free-swimming stage. However, in pure freshwater.

    Why do they often refuse to spawn, I can not answer. That certainly depends on the ambient conditions. IF they even begin to spawn, then they do it often. But until the first time it may take a long time.

     

    I look at once what you have written there :-)

     

    #349524

    Ferrika
    Participant

    Hi Matt,
    two things I noticed for R. candidianus:

    First Rhinogobius should please NEVER be kept in pairs (the only exception is R. giurinus, the males are very aggressive with each other). For all other Rhinogobius types need the males to interact with other males in order to behave in normal and active. In individual housing, there are often strong inactivity and can also lead to, among other things, that no longer is being hatched.

    Second the risk of hybridization is at the R. candidianus only with R. cf. nantaiensis and possibly with R. cf. henchuenensis. In other ways they can be quite hold together, but are R. candidianus relatively pugnacious and argue with equal types and across species.

    In this context one should mention at the R. candidianus also sometimes available before the aggression towards other aquarium fish. They are not necessarily socially acceptable.

     

    For the R. cf nantaiensis maybe you should bring a small warning: the clutches are very large (up to 450 eggs) and the survival rate also. On my first clutch I had over 150 offspring from one clutch.

     

    In both species, the larvae are pelagic!

    #349529

    Matt
    Keymaster
    Much appreciated, thanks a lot Jutta! I’ve made those changes but have a couple more questions:

     

    – do the larvae still have some yolk sac remaining when they hatch? Do they become pelagic immediately after hatching?

     

    – approximately how long is the pelagic phase of the life cycle?

    #349534

    Ferrika
    Participant

    Hi Matt,

    They have after hatching a relatively large yolk sac, which is sometimes used up after 6 days.
    They swim but still immediately on (if they are not hatched too early).

    In the R. cf. nantaiensis it takes about a week to go down.
    The R. candidianus go after about 3 weeks on the ground.

     

    Have a look at these pictures :-)

    http://das-grundelforum.de/zucht/rhinogobius_candidianus_es_tut_sich_wieder_was_121.msg2475.html#msg2475 and

    http://das-grundelforum.de/zucht/rhinogobius_nantaiensis_460.msg5750.html#msg5750

    #349535

    Matt
    Keymaster

    Some great pics and love the way videos are included too. :)

    How big is the male in the last image of the R. nantaiensis thread? Beautiful specimen and I’m starting to be more convinced about the id…

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