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Sexing silver dollars

Discussion in 'Cyprinids, Characins and Atherinids' started by kat and james, Aug 23, 2005.

  1. kat and james

    kat and james Member

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    hi
    we've got some silver dollars and were just wondering how you can tell their sex, as one of ours has a very circular body, while the other two have a slightly elongated body.. just wondering whether that had anything to do with it!
    thanks
    kat and james
     
  2. Lateral Line

    Lateral Line It's full of stars

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    Their are several similar species which get called "Silver Dollars". Most grow large, and the males tend to develop a longer anal fin which in some species will become quite red.

    BTW, SD's are known as lawn mowers in tanks, you probably won't have your plant problems much longer! You won't have your plants!
     
  3. kat and james

    kat and james Member

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    yea, we knew they'd chomp the plants when we bought them, but they only seem to have taken a fancy to these reeds, they leave the java fern alone. we have also tracked down some discus.. hence silver dollar proof plants!
    i also read somewhere that you should keep silver dollars in a planted tank, as it's good for them to have the plants to nibble on.
    i'm not too worried about them eating the plants anyways!
    thanks
    kat and james
     
  4. Lateral Line

    Lateral Line It's full of stars

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    >>> we have also tracked down some discus

    Errr, this is a vaguely worrying comment. You realise, of course, that discus require somewhat more specialised conditions...
     
  5. Kajuki18

    Kajuki18 Member

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    JW what size tank do you have?
     
  6. kat and james

    kat and james Member

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    sorry.. i didn't explain that well.. just meant these plants are hardy, and the silver dollars tend to leave them alone. they don't need any special requirements, same as the other plants in the tank
     
  7. Lateral Line

    Lateral Line It's full of stars

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    SD's usually clear everything eventually. You can reduce their plant destroying habits by copious feeding with other vegetable matter, courgette, cucumber, lettuce etc.

    I am confused actually...

    >>> we have also tracked down some discus

    ... when you say discus, I straight away think of discus as in the South American cichlid fish. Yet you don't appear to mean that?
     
  8. kat and james

    kat and james Member

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    right i get what you mean now.. what i meant was that we found some "discus-proof" plants, which also results in them being fairly silver dollar proof also!! and it seems to work.. sorta!
    wanted to ask, we give cooked peas and cucumber to the fish, but how do you give them lettuce.. i read somewhere it needs to be cooked.
     
  9. Lateral Line

    Lateral Line It's full of stars

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    Not cooked as such, dropped for a few seconds into some boiling water "scalded". Most green vegetables will be suitable.
     
  10. CFC

    CFC Leader of the Fishes

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    You dont even need to blanch lettuce for silver dollars, those lawnmower teeth go straight through even the stalk on lettuce that has simply been rinsed under a tap.

    Ive yet to find a SD proof plant, mine have managed to eat java fern, anubias and giant vallis without any problems. If you really want plants in a SD tank buy silk ones, they will last longer and cost you less in the long run.
     
  11. Lateral Line

    Lateral Line It's full of stars

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    Blanched, yes, that was the word I was looking for. You're right of course, a big SD will destroy it unblanched.
     
  12. kat and james

    kat and james Member

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    ok thats cool.. will get on that.. they seem to demolish cucumber! how do you weigh down the lettuce? we have this thingy called a screwcumber for the cucumber works like a dream!
    :p
     
  13. CFC

    CFC Leader of the Fishes

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    Ask in the lfs for a lettuce grip, its like a plastic bulldog clip with a suction cup to attach it to the glass.
     
  14. kat and james

    kat and james Member

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    bought one yesterday! have yet to use it.. but i'm looking forward to using it.. i much prefer giving them live food or fresh food than the regular fish flakes! feel like a mum trying to get kids to eat their greens.. lucky me my fish prefer thier greens anyways!!!!!!! ;)
     
  15. ricardo

    ricardo Member

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    i dont know really about the the two different types all i know is the male has got a little red on its bottom fin
     
  16. Dangerousdan

    Dangerousdan Moved On

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    True silver dollar Mylossoma duriventre are manic green eaters. I have 3 around 4 1/2" disc size and these things eat anything...and lots of it.
    I also have 2 Schreitmullers Metynnis Metynnis hypsauchen around 5", these seem to appear more in LFS than the true silver dollars. No where near as distructive to the plants but still have a nibble.
    The later have a red tinge in anal fin and lot smaller eyes. The former has red tinge on edge of caudal fin and dorsal fin. Also small black colouring on tip of dorsal.
    Mine also have faint black spot shape just after the gill plate.
    Dan
     
  17. CFC

    CFC Leader of the Fishes

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    In European litterature the common name Silver dollar is given to Metynnis argenteus though tanks of silver dollars seen in stores can be either M.argenteus or M.hypsauchen. They can be told apart when adults as mature M.argenteus have black dots on their sides where as M.hypsauchen do not.

    Mylossoma duriventre is a fairly rare import and is usually commonly called the Silver Mylossoma
     
  18. Dangerousdan

    Dangerousdan Moved On

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    Thanks for this interesting post CFC, spent few hours this moring trying to find out what species my dollars are :S
    Will post some pics of mine later but in mean time heres some i found on net that look same as mine.

    This is the fish i labelled as Mylossoma duriventre, which is what this pic was labelled as. I have 3 that look exactly same as this.
    [​IMG]

    This is the fish i labelled as Metynnis hypsauchen, which is what this pic was labelled as too. I have 2 that look exactly same as this.
    [​IMG]

    This is also what my 2 ref books have these fish labelled as. Whats the best site for getting accurate ID? Seems to be so many that have bad information :angry:

    Picture credits:badmanstropicalfish.com
     
  19. CFC

    CFC Leader of the Fishes

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    The top photo is a Metynnis argenteus, Mylossoma duriventre has a hook shaped dorsal fin and an anal fin which is thicker toward the tail than it is toward the anal vent. It also has a more pointed shaped mouth. Check out this link to see pics of a true M.duriventre http://kingsoftheaquarium.com/characins/mylassoma11-10.2.jpg

    The bottom fish could be either a M.argenteus or M.hypsauchen as they are difficult to tell apart as juviniles.
     
  20. Dangerousdan

    Dangerousdan Moved On

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    Thanks
    If the top fish is a Metynnis argenteus then the others definitly are not as the body shape is completely different. The 3 i have same as top pic have a kinda stretched look to there bodies where as the 2 i have same as bottom pic have a much rounder look to them and their eyes are much smaller. Oh and also a much brighter shiney silver colour.
    Cheers for all information
    Dan

    Ill take soom pics when i get home from work.
     

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