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Silver Perch Bidyanus bidyanus

Discussion in 'What Fish is that ?' started by dufflight, Feb 21, 2010.

  1. dufflight

    dufflight Member

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    Difficulity in keeping - Easy
    Feed - Pellets, yabbies, plant material(duckweed), BSFL
    Ideal tempreture - 22 to 28
    Min & Max tempreture - ??
    Growout time - ??
    Common names - Grunter, Murray perch, silver bream, bidyan

    Fingerling
    [​IMG]
    Adult fish
    [​IMG]
    Please fill in any of the blanks or add any details. They can be edited into the post. Also if any one has a better picture.
     
  2. Castaway

    Castaway Senior Member

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    Temperature tolerance ranges from 20°C to 35°C. Optimum growth rates occur between 20°C to 30°C with negligible growth below 12°C. Marketable fish of 400-600 grams can be grown in 10-12 months.

    Some good info can be read here: http://www.dpi.qld.gov.au/28_13349.htm
     
  3. RupertofOZ

    RupertofOZ New Member

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    Up north,and if you get advanced fingerlings at the start of summer... maybe...

    Much more likely... 12-18months...
     
  4. Julia

    Julia New Member

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    You could add worms to the feed list. My silvers have a feed of worms in the morning, pellets in the afternoon. They much prefer the worms.
     
  5. desertrat

    desertrat New Member

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    I feed small amounts of duckweed to the Silvers every second day
     
  6. ColinW

    ColinW Member

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    Last edited: Mar 30, 2010
  7. ColinW

    ColinW Member

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  8. ColinW

    ColinW Member

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    Silver Perch eat Won Bok leaves infested with Aphids - threw this Won Bok into Fish Tank yesterday - this is what is left today.
     

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  9. fishfood

    fishfood Active Member

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    I have just put 2 pots of waterlillies in with my silvers we will see how long they last
     
  10. erina george

    erina george New Member

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    my 100 20cm silvers will strip a bolted lettuce in 10 minutes
    i alternate overgrown lettuce with fresh sweet potato runners 50-80 cm long daily
    the growth of the silvers has been astonishing
    i am using grobest 4mil pellets
     
  11. Julia

    Julia New Member

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    Thanks for the tip on the sweet potato runners as feed for silvers. Have been trying celery leaves - they'll eat those overnight, but don't seem interested during the day. . .
     
  12. RupertofOZ

    RupertofOZ New Member

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    You'll find that's the case with most plant stuff Julia.. the Silvers seem to primarily eat it overnight...
     
  13. Julia

    Julia New Member

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    Hi Rupert,

    Interesting - I thought maybe they just were dawn eaters. What time of day do they prefer to eat their protein?
     
  14. RupertofOZ

    RupertofOZ New Member

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    Depends on water temperature.. and stage of growth Julia...

    With water temps of 24-26... fingerlings would be fed 4-6 times a day...

    My tank is currently at those temps ... with most fish above 5-600gm... and I'm feeding three times a day...

    About 10:00, 13:00 and 17:00..... partly because the light hits the tank until about 09:30....
     
  15. Julia

    Julia New Member

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    How much are you feeding your bigger fish at these temperatures, Rupert? I have about 40 fish, a bit smaller than yours (various sizes), and feed them around 9.30 am (4 tablespoons of pellets) and 40-50 gms of worms in the afternoon at around 4.30pm. When I fed them in the middle of the day, most of the pellets were wasted. The temperature in my tanks are about the same as yours, on a sunny day.
     
  16. Murray

    Murray Site Admin Staff Member

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    Sorry to jump in Julia, but it could be because they are hanging out for the worms....I have discovered a similar behaviour with my Barra.
    Occasionally I go down to the dam and net a few hundred of those "mosquito" fish and deliver them to the Barra tank.....the Barra go mad and clean them all up quick time.. (it is a tough life for small fish)
    The Barra have no interest in the pellets for a couple of days after the feed of live fish, and then only gradually come back onto the pellets. Let's face it, those pellets must be pretty boring for breakfast, lunch, and tea...
     
  17. RupertofOZ

    RupertofOZ New Member

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    I wouldn't sweat it Julia... if they're not interested in the pellets midday...

    Fish do get used to your feeding regime... and either wont take other feeds, or may take several weeks to get used to a new regime...

    Mature fish only really need feeding 1-2 per day... I tend to feed more often, depending on water temps, but spread the feed ration over the feeds...

    Rule number one... is if they fish aren't interested... stop feeding.... you're just wasting feed and compromising your water quality...

    Attached below is the Silver Perch feeding strategy developed by Stuart Rowland (Head Researcher Grafton DPI)... which shows pellet size and daily feed rate (% of biomass) ... for various stages of growth and varying temperatures...

    Biomas can be determined a couple of ways... get a container full of water, tare your scales... then net 5-10 fish....

    Average the weight of the fish sample... and multiply by the number of fish you have...

    Or, as a rough guide... well actually, the graph represents real data.... either measure or estimate the length of your fish... and using the graph below determine the average weight...
     

    Attached Files:

  18. Julia

    Julia New Member

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    Murray: I agree with you there! I'm sure they prefer the worms to the pellets. When they're really hungry in the morning, they're happy to eat pellets, but they'll eat worms any time of day. (I'm too lazy to bother with the worms more than once a day.)

    Rupert: Thanks very much for the table and graph - they're very useful. Do you find that you're feeding the amounts indicated on the table for your size fish?
     
  19. RupertofOZ

    RupertofOZ New Member

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    The feeding strategy represents recommendations for optimal growth...

    I probably under-fed my Silvers initially ... due to lack of filtration...

    And on occasions, haven't fed them at all for several days while I've been away...

    Sometimes, particularly if a front is coming through... they're not that interested... and I'll only partly feed them...

    Be guided by your fish response to feeding... and your water quality...

    Generally, yes, I feed pretty close to the recommendation...many people probably overfeed, many probably get away with it... but excess feed is wasted money ultimately... it often doesn't convert to flesh, just fat, or more wastes... and usually doesn't make them grow any faster....
     
  20. Julia

    Julia New Member

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    Thanks for all the info, Rupert. I find it very difficult to estimate the biomass - there is such a huge range of sizes, so I just have a look after ten minutes or so and see how they've gone, then switch the pump and aerator back on. When the temp is over 23 degrees, they'll eat happily three times a day, but like you say, when it's raining or a front's coming through, that can put them right off. And it's amazing how much just a few degrees in temp affects the feeding rate. Very interesting.
     

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