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Thread: The Forest Stream

  1. #16

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    Quote Originally Posted by Spidy View Post
    Don't eucalyptus leaves excrete a substance that is poisonous to fish?
    I’ve heard that “myth” before, and to that I say: surely if the eucalypt leaves were truly poisonous to fish, shouldn’t the local creeks and streams be full of dead fish? There are many streams that run through karri or jarrah forests in the southwest, they’re black as coffee from all the tannins, and yet they’re full of native fish. Plus I’ve never experienced any eucalypt-related fish deaths

    Quote Originally Posted by bald_noggin View Post
    Nice work. Looks great.
    Thanks!

  2. #17
    Join Date
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    Melbourne, Australia
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    Quote Originally Posted by pseudechisbutleri View Post
    I’ve heard that “myth” before, and to that I say: surely if the eucalypt leaves were truly poisonous to fish, shouldn’t the local creeks and streams be full of dead fish? There are many streams that run through karri or jarrah forests in the southwest, they’re black as coffee from all the tannins, and yet they’re full of native fish. Plus I’ve never experienced any eucalypt-related fish deaths


    Thanks!
    Yeah, I thought that too but streams have constant flow, aquariums are closed systems. I'll do some research and report back.....

  3. #18

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    Not just streams.... ephemeral pools, those that aestivating species inhabit, are far more acidic (sometimes as low as 3.0) and extremely tannin-stained than streams. No flow either

  4. #19

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    So I thought of this idea today and I thought it was pretty good. So every 24 hours, I'll swap out one of the spawning mops into a "fry tank", for the eggs or fry to drop out of the the spawning mop. The fry tank has an airstone for oxygenation.


  5. #20
    Join Date
    Jun 2013
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    ACT
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    13,969

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    Quote Originally Posted by Spidy View Post
    Yeah, I thought that too but streams have constant flow, aquariums are closed systems. I'll do some research and report back.....
    Here is an except to get those tanin juices flowing....





    Leachates of Eucalyptus globulus in Intermittent Streams Affect Water Parameters and Invertebrates
    Cristina Canhoto, Celia Laranjeira
    International Review of Hydrobiology 92 (2), 173-182, 2007
    Low order streams running through Eucalyptus globulus plantations in Central Portugal are frequently reduced to isolated permanent or temporary summer pools with darkly stained water due to leaf leachates. Here we assess the toxicity of such leachates to the shredder Sericostoma vittatum. Leachates resulted in deoxygenated and more acid water, and increased its phenolic content and conductivity. S. vittatum exposed to high concentrations of leachates failed to grow and died within 30 days even in the presence of high quality food. Larvae in water with half the leachate concentration, consumed less leaf material, had lower growth rates, did not pupate and died within 100 days. Eucalypt leachates per se may affect the viability and ecology of macroinvertebrates in Portuguese streams. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
    View at onlinelibrary.wiley.com
    [PDF] uc.pt
    Cited by 73
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    Eucalyptus leachate inhibits reproduction in a freshwater fish
    John R Morrongiello, Nicholas R Bond, David A Crook, BOB BM WONG
    Freshwater Biology 56 (9), 1736-1745, 2011
    1. Dissolved organic carbon (DOC) can induce lethal and sub‐lethal effects in exposed biota via hypoxic blackwater events and the toxicity of leached compounds. Little is known of how DOC exposure affects fish reproduction despite the fact that its release can coincide with spawning‐associated flow pulses.
    2. River red gum (Eucalyptus camaldulensis) leaf leachate is a major source of DOC in Australian freshwaters and includes the toxic plant secondary metabolites polyphenols and tannins. High concentrations of leachate are released when leaves on floodplains or dry stream channels are inundated by water.
    3. Southern pygmy perch (Nannoperca australis) from naturally high and naturally low Eucalyptus leachate environments in south‐east Australia were exposed to elevated leachate levels to investigate the effects of DOC on reproduction and to explore whether response patterns were consistent with populations becoming locally adapted to historical leachate levels.
    4. Fish exposed to leachate were half as likely to reach sexual maturity as control fish. Fish from a naturally high‐exposure population tended to reach sexual maturity earlier than those from a naturally low‐exposure population. Leachate exposure had no effect on either egg size or fecundity.
    5. Our results suggest that leachate‐exposed mothers did not reproduce because they were physiologically stressed or perceive the environment to be unsuitable, which raises the potential of plastic or adaptive responses to this stressor. The negative sub‐lethal effects observed have important fitness implications for individuals, the viability of populations and the management of environmental flows and riparian zones.

  6. #21

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    Well shoot

    Reminds me of a paper done on three species of native fish and their tolerance of hypoxic conditions. Coincidentally, the two species that are most tolerant of hypoxic conditions are mostly found in extremely stained ephemeral swamps (nigrostriata and salamandroides, both also aestivate...

  7. #22

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    Nothing new to document, the stability is nice though

  8. #23

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    Something I hate is slime algae and it's starting to appear in the tank. I've tried to scrub it off with an old toothbrush, but the little buggers reappear within 24 hours Interestingly though, I have another tank with the same params (pH of ~6.4), but the only difference is that presence of tannins in the water. That tank has much less algae growth. Hmmmm...



    Here's a nice group pic

  9. #24
    Join Date
    Jun 2013
    Location
    ACT
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    13,969

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    Do you have any glass shrimp? If so chuck a 100 or so. They eat slime.

  10. #25

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    Oh cool, never knew that. I had some a few days ago that I gave away, I'm gonna have to get some more then
    Last edited by pseudechisbutleri; 20-08-19 at 08:46 PM.

  11. #26

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    the green slime is blue green algae (Cyanobacter bacteria). It love dry food, low oxygen levels and will thrive under most conditions in fresh, brackish and saltwater tanks. Try to syphon it out each day, reduce the amount of dry food going into the tank, and increase water movement/ aeration. It usually goes when the tank settles down and the nutrients are reduced.

  12. #27

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    I don’t even feed the fish dry food, always figured that live and frozen was more nutritious. Maybe I’ll just swap out the return pump for a stronger one (currently 550l/h), might even hook up a Venturi apparatus.

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