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Byron Hosking

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Viewing 15 posts - 121 through 135 (of 150 total)
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  • in reply to: Nannostomus – adipose fin #352894

    Byron Hosking
    Participant

    Your last sentence may be the answer, on two fronts.  Could this species be N. digrammus?  Looks similar to me, but photos are not always easy in identification.

    There are some photos supposedly of N. minimus here

    http://apisto.sites.no/fish.aspx?FishIndexID=2469&gruppeId=5

    though I’ve no idea as to the reliability of the species ID.

    In the species N. eques the adipose may or may not be present, according to Weitzman.  I have this species, and the adipose fin is so tiny I can barely see it but it is present at least on some of my fish.  I also have the similar N. unifasciatus which is supposed to have an adipose, but mine do not, unless here again it is so miniscule I just can’t see it.  It would seem that there is some variation within certain species in this genus.

    Weitzman and Cobb (1975) is not a recent work.  Weitzman (Stanley and I believe his wife Marilyn) supplied the data on these species for the 2003 Checklist…does anyone have access?  I did once, but now can’t seem to get it online.  It is pages 241-251.  This might have something more recent?

     

    Byron.

    in reply to: R. dandia synonymised with daniconius? #352884

    Byron Hosking
    Participant

    @coelacanth said:
    It was that paper that helped lead to the conclusion that what we have are dandia and not wilpita as originally thought, but dandia is no longer listed on Fishbase (I’m sure it was previously), instead you are directed to daniconius.

    It may be that for some reason Fishbase has missed this.  Dr. Eschmeyer who maintains the database at California Academy of Science has the references I cited previously.  These two sources are usually in sync.

    in reply to: R. dandia synonymised with daniconius? #352882

    Byron Hosking
    Participant

    According to Eschmeyer, Leuciscus dandia was placed into synonymy with Rasbora daniconius by Brittan (1972), but Silva, Maduwage and Pethiyagoda (2010) re-established it as distinct and in Rasbora.

     

    Here’s the latter paper:

    http://www.pfeil-verlag.de/04biol/pdf/ief21_1_03.pdf

    in reply to: Red-nosed tetras #352593

    Byron Hosking
    Participant

    @Matt said:
    Cheers Byron, this is actually the same one I used when doing the profiles. :)

    Great minds…, I guess.Wink

    I have another which has no text, just a photo and illustration of each of the three species; also not sure where this came from.  The earlier with text is a bit clearer.

    Byron.

    tfh_rummynose_tetras.jpg

    in reply to: Red-nosed tetras #352569

    Byron Hosking
    Participant

    Thanks Rudiger, here goes.

    This is the illustration of the three rummy’s.  I think this came from Sterba, but not certain.  I’ve had it for a while.

    Rummynose-chart.jpg

    in reply to: Red-nosed tetras #352567

    Byron Hosking
    Participant

    @Matt said:
    Hi Byron, click the ‘Upload Attachments’ button underneath the text field when replying in a thread. This opens a drop-down box into which you can drag files or add them using the ‘Add files’ button. Once the files appear in the box click ‘Start Upload’ and wait until they appear in yor reply before adding the reply as normal.

    Hope that helps!

     

    When I click “Add Files” button, nothing happens.

    in reply to: Red-nosed tetras #352563

    Byron Hosking
    Participant

    Byron, do you have any photos of your Petitella – would be great to see them!

    Hi Matt…I’ll try to take some, but my camera is not the sort that captures clear photos of anything moving.  Is there an instruction here as to uploading photos from a PC?

    Byron.

    in reply to: Nitrogen cycle and nitrifying bacteria #352554

    Byron Hosking
    Participant

    Possibly, but I would select another brand.  I don’t know this product myself, and from what I see on the manufacturer’s web site [http://www.aquasonic.com.au/product/bio-culture-standard-100ml/] it contains three strains of bacteria, namely Bacillus Strains, Nitrosospira and Nitrospira.  They say Nitrosospira is responsible for the ammonia to nitrite exchange, but I believe this is in soil not water.  Dr. Tim Hovanec led a team of scientists some years back who determined that Nitrosomonas bacteria handle this stage in fresh and marine water, and Nitrospira probably the second phase (nitrite to nitrate).  Myself, I would not use this product but another containing these.

     

    Dr. Hovanec has one of his own products, “Dr Tim’s Onew and Only,” and there is also Tetra’s SafeStart (which is Dr. Hovanec’s original formula that he sold to Tetra).  And I have successfully used Seachem’s Stability in new tanks.  With all of these, they quicken the bacterial colonization but don’t replace it as an instant cycling; although Dr. Hovanec does claim this for his own product.  I treat these bacterial products as forms of seeding bacteria, and they do that without question.

     

    On the issue of cycling, live plants is my preference.  With sufficient fast-growing plants, especially surface (floating) species, you don’t even see the ammonia/nitrite with tests because the plants grab the ammonia and usually out-compete the bacteria.

     

    Byron.

    in reply to: Red-nosed tetras #352551

    Byron Hosking
    Participant

    I came across an illustration some years back that to me is helpful.  I can’t figure oput how to attach it from my PC, so here is my description of the differences.  H. bleheri is certainly the most colourful and is now the most commonly available of the three, and the one almost certain to be in shops as “Rummy Nose” or similar. This species is easily distinguished from the other two; only in this species does the red colour extend beyond the head onto and past the gill covers. Also, the central caudal fin band extending laterally onto the body of the fish that is quite evident in the two similar species is almost non-existent in H. bleheri. The red colouration is brightest in this species, though this can be misleading as it pales if the fish is under stress and it usually would be in dealer’s bare tanks. The “original” Rummynose, H. rhodostomus, is unlikely to be encountered today; I have never seen it locally, but perhaps it is encountered in the UK [I’m in Vancouver, Canada].  P. georgiae is sometimes available and when housed with H. bleheri the two species will all remain together.  I have had two groups of both species together for three years now, and they have remained tightly shoaling as one group.  It is fairly easy to differentiate them from the red intensity and the caudal fin bands.  Petitella georgiae has in my case anyway grown slightly larger too.

     

    Hope this helps.

     

    Byron.

    in reply to: Low PH Nitrogen Cycle #351740

    Byron Hosking
    Participant

    I may be able to add a bit.

    As has been mentioned, the low fish load to water volume in nature plus the ever-moving water (in streams and rivers) means that ammonia is not likely going to affect fish, barring some disaster.

    Turning to the aquarium, the pH of the water being acidic means that ammonia is changed into ammonium, and this is basically harmless to fish.  My several tanks have for more than 20 years had a pH around 5 in some, 6 in others, and they are full of fish (mostly wild caught).  I have never had ammonia or nitrite above zero when I tested.  I also have live plants which grab the ammonium fast, and actually out-compete the bacteria/archaea all else being equal.  So in your (amazonrain) situation, I wouldn’t worry at all.

    On the bacteria itself, from my admittedly not exhaustive research I have found that with respect to pH, the nitrifying bacteria operate at close to 100% effectiveness at a pH of 8.3, and this level of efficiency decreases as the pH lowers.  At pH 7.0 efficiency is only 50%, at 6.5 only 30%, and at 6.0 only 10%.  Below 6.0 the bacteria enter a state of dormancy and cease functioning. Fortunately, in acidic water (pH below 7.0) ammonia automatically ionizes into ammonium which is basically harmless, as I mentioned above.  And since nitrite will not be produced when the ammonia-oxidizing bacteria are in “hibernation,” this decrease in their effectiveness poses no immediate danger to the fish and other life forms. 

    Temperature also affects the rate of growth of nitrifying bacteria.  It will be optimal at a temperature between 25 and 30C/77 and 86F.  At a temperature of 18C/64F it will be 50%.  Above 35C/95F the bacteria has extreme difficulty.  At both 0C/32F (freezing) and 100C/212F (boiling) the bacteria die.

    A study published only last year suggests that in established aquaria, it is not bacteria but rather archaea that perform the nitrification.  I’m fairly certain that Matt posted about this a while back, but you can read the entire paper here:

    http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0023281

    Hope this is of some help.

    Byron.

    in reply to: Nannostomus mortenthaleri #316699

    Byron Hosking
    Participant

    33g-Apr-6-12.JPGI acquired a group of 8 wild N. mortenthaleri just over a year ago (Feb 2011) with 4/4 male/female.  They settled in very easy, and have spawned regularly for several months now.  I just let nature tanke its course, so survival of eggs/fry is haphazard, but I have had two fry survive recently (without any intervention from me).  They are in a 33g (3-foot) tank with sand, lots of bogwood chunks (some covered in Java Moss), and mainly Helanthium tenellum in the substrate, a “red” Echinodorus cultivar, and a couple of Echinodorus parviflorus “Tropica,” and a thick canopy of Ceratopteris cornuta floating.  Water is 77F, pH 5 or lower (can’t measure below 5 and it is certainly that), hardness was initially zero but since January I have been using Equilibrium at each water change to maintain GH at 5 dGH.  KH is zero (my tap water is near zero GH and KH).  The pygmy swords were languishing without sufficient calcium and magnesium, hence the Equilibrium.  The pencils don’t seem to have minded this, they are still spawning regularly.  Photo of this tank attached.

    Byron.

    in reply to: Revisión Del Género Apistogramma Regan, 1913 #347972

    Byron Hosking
    Participant

    Yes please, and thanks.
    Byron.
    [email protected]

    in reply to: Xiphophorus and Poecilia spp. #347948

    Byron Hosking
    Participant

    I have the Jacobs book mentioned earlier by coelacanth; in the chapter on Reproduction he writes:

    In 1903 Johannes Peter pointed out that no one had succeeded in producing a hybrid between two genera “because such a cross would be prevented by the differing structure of the sexual organs.” In 1912 there was a report of a hybrid between a male Poecilia mexicana and a female Molliensia latipinna and this was hailed as the first intergeneric cross. According to modern ideas on systematics this does not appear so wonderful, because both these species are now classified in the genus Poecilia. [note below]
    Nowadays one can state that the livebearers will hybridize in aquarium tanks and the crosses are, in general, interspecific or at the most intergeneric. By applying the Mendelian rules of heredity it is possible to produce some very beautiful forms within the genus Xiphophorus and also in the Guppy.
    [There then follows some discussion on sperm differences and so forth.]
    Successful hybridization can only be achieved if one to three females are put together with only a single male of the other species. Even then it is necessary to experiment. … If this male does not mate with the females within 10-14 days, the attempt must be repeated using a different male. This experiment must be patiently continued until a male does finally mate with a female.

    A note on the Poecilia species: Some ichthyologists have recently proposed that the guppy does not share certain specific traits with the other molly species and should be separated. Poeser et al. (2005) suggested re-validating Acanthophacelus, originally erected by Eigenmann in 1907 and subsequently deemed a synonym for Poecilia, as a subgenus, and Schories et al. (2009) follows this but proposes that the entire genus Poecilia is in need of revision.

    I initially asked the question of Matt, so thought I should try to offer something to the discussion.

    Byron.

    in reply to: Pantodon buchholzi #345000

    Byron Hosking
    Participant

    When I had a pair of P. buchholzi many years ago I fed them several chunky foods. Plankton (frozen and freeze dried), frozen squid (highly nutritious), freeze dried bloodworms. I also had mealworms (easy to culture year-round in an old fish bowl) and the beatles if dropped on the water surface near the fish would really get them excited. Some of the prepared foods will sink, so I used a small piece of broomstick to “spear” the chunk of squid, etc. The fish would almost leap up to get it.

    Byron.

    in reply to: Hyphessobrycon peruvianus — Hemigrammus lunatus #341453

    Byron Hosking
    Participant

    QUOTE (Steve Waring @ Feb 27 2011, 11:27 AM) <{POST_SNAPBACK}>
    My LFS has been selling Lime Green Tetras Hemigrammus lunatus for some time now. To my untrained eye they look very similar to pictures I have seen of the Peruvian Tetra Hyphessobrycon peruvianus.

    Does anyone know any distinguishing features?

    They may be misnamed, as from the photos I’ve seen the Hemigrammus lunatus is thicker bodied whereas Hyphessobrycon peruvianus is more pencil-shaped. Photos attached may help.

    The H. peruvianus is very similar to H. metae. Gery opinioned they might be the same species, or sub-species. They are recognized as distinct species today, though all species in both genera are liable to change. When I first acquired H. metae I thought it might be H. peruvianus, but Heiko Bleher had a look and sorted it out for me.

    Byron.

    Attached files

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