DNA sexing with fish

[Ben]

Hi All!

has anyone out there heard of dna sexing of fish?
i know it is done with birds in melbourne, it costs arond $50 per bird, a feather is used to test for the sex chromasone and it is %100 accurate!

i just wonder if it is possible to do with fish?
or do they do it already here or overseas?

i would love to hear about this if any one has any answers!

[weird]

prodigydiscus, I like your posts more and more. You think outside the circle ... dude I like that :D

[flukes]

There is venting which is near perfect if performed by someone who knows what they are doing. DNA would have too be possible but at what cost. Bit harder that getting a feather from a bird..

[Ben]

ok...but.... if i was to tell you i could supply any age discus(maybe 3cm +) with a written guarantee that they were either male of female this would or could make a whole new world to discus keeping and breeding!

example,

i dna sex 30 red melons,
18 are male
12 are female

i grow them up, females in 1 tank, males in another,
and at 18 months of age(or sexually maturity) i pair them up! there would be no wasting time, like i am having at the moment (see post lesbian discus) with who's laying the eggs etc!

then male could be sold as males or swapped with other breeders with females.

as for the price, well is it worth $50 a fish to know exactly what sex it is???

me personally...i would pay that! it could save 12 months or more!

With venting, i would presume the fish is taken out of the water and closely inspected, how long would it take to check its vent? and what would be the guarantee in doing that method?

All that would have to be required is a very small piece of the tail fin removed, when i say small it could be 1mm by 2mm piece.

going back to the venting method, up until 4 years ago, birds were surgically sexed, yes there was a %100 guarantee that it was either a male of female, but the birds go through a lot of stress with this method. catching a discus, using a sharp razor blade and cutting a piece of tail fin, would be no more stressful than transfering the fish to a new tank.

i would love to hear more about this subject!
so guys and girls please post your replies!!
Ben

[dreamer]

at 3cm you can hardly decide whether the fish is a keeper or cull, maybe 10cm?

i personally woudnt pay extra for dna test, just let the fish grow and nature take course. what i want is big and beautiful discus :)

[flukes]

So using your example you said having a batch of 30 red melons, so you would pay $1500 just too know there sex??

The venting isnt anymore stressful on the fish than shipping it half way around the world.

Iam not saying it isnt a good idea, i just think its a bit early yet too be thinking of doing it at this level of the hobby. Sure it maybe worth $50 a fish for some of the Penang farms that could easily recoupe their looses.

I do think its a good idea but for $50 id rather take my chances with fins and tubes..

[Sean]

IMO sexing of fish can be done a lot more cheaply than using DNA. My work is in this area and I would love to set up a test using DNA and charge $50.00 per tail clipping. However, it would be a hassle to setup the assay. I have sexed Oscars and other egg laying cichlids by giving them an injection of hormones which induce them to lay within 24 hours. This information is freely available on the web (eg. http://www.intervet.com/aah/chorulon.asp) however, I have determined which of my 17 discus are males and females by simply pairing individual fish with my known female ie. one that has laid eggs. Usually she will lay eggs within a week with a new partner - place a gutter guard barrier around the eggs, get wrigglers and you not only know you have a male but a fertile one at that - much more valuable info than a DNA test will give and heaps cheaper.
If anyone wants to know more about the hormone inducing method and knows a friendly vet sing out and I will provide you with the dose.
Sean

[Ben]

flukes, thanks for you feed back.
its all very interesting, we can spend hundreds of dollars on tanks, filter's, chemicals, fish and even the food we feed them, but to spend $50 to know what the sex of a fish, in my opinion this is nothing, if it was me yes i would spend $1500 on 30 red melons to acuratly know their gender.
if it can be done, work out aprox how much it would cost to house, feed and generally maintain 1 single discus, lets just say its life span is 7 years, another 50 dollars would most likely be nothing compared to that!

Dreamer made a post, "let nature take its course"
well, did nature intend on having mosaic, snakeskin, albino and hundreds of other highly coloured discus? look at nature, the discus in the wild look rather plain than the above ones mentioned.
in saying all of this, we now live in a world of technology and advancedment, so we breed discus to get different colours, pattern and even body shape, why not go one further and dna sex discus?

[Ben]

Sean, some discus breeders/keepers might think that dna sexing is a bit over the top, but i had a look at the CHORULON, i know it is cheaper but let me quote this:

"Chorulon should be administered via intramuscular injection just ventral to the dorsal fin for one (1) to three (3) injections. Any single injection should be administered, depending on the fish species, at a dose of 110 to 1122 I.U./kg body weight (bw) for males and 147 to 3995 I.U./kg bw for females"

Taking a piece of fin of the fish, then sealing it in a bag seems a bit easier.

[Sean]

DNA will also provide the sex of immature specimens which I omitted from my last post. Injections with the right guage needle and syring are no hassle - but I suppose I have done it before - it takes less than 30 secs, stresses the fish, but probably less than changing tanks IMO. I wouldn't recommend the hormone method to anyone who is not confident in handling fish and needles. But nonetheless it is a method that I think is better than DNA testing and potentially can provide a batch of fry if the parents are willing :wink:

[Ben]

Sean, what would it cost? let say for 5 fish?
cheers,
ben

[dreamer]

they did found snakeskin in the wild but not the rest though, its natural cross :)

what im saying is, im enjoying my discus in quality (size, color, bodyshape) i dont really care whether they are m/f as im dont really intend to breed them
(time/space constraint)

but again, how many ppl willing to pay extra $50 for small fish ie. 3cm??

good breeder dont just throw in 1m 1f in the tank and let them breed. they select the highest quality from their stock, thats how they earn their reputation. what is the point having so called guaranteed m/f if they are just not up to the standard?

but again, this is just my personal opinion..if i have that amount of money to sex discus ...i rather to spend it on other exotic fish ... like L no pleco ..right kev? :lol: :wink: *wink*

btw, i like wilds more than domestic :)

[Ben]

dreamer, thanks for you feedback.

i know that breeder dont just throw a male and a female together, they get the best fish from thier stock, but they could match up the best female with the best male a lot earlier than if they had to naturally wait until the best paired them self.

i guess it would be a head start
so yes it could be a waste of time and money dna sexing the fish at 3 cm but lets turn it around and say 10cm +, you would already know by colouring/ marking /body shape etc which are the elite fish so you could pair them up with less waiting.

i personally like wilds too, but i guess the colour mutations have there place and are in a different catagory.

[Ben]

Discus forum members, i am going to start a poll on "to dna sex discus or not to?"

[Trebs]

From a hobbyist breeder point of view, I can't really see any value in DNA sexing.

You really want to put your energy(and cash) into finding discus that are tape worm and gill fluke free, haven't been exposed to discus disease and that aren't hormone treated(which can leave the fish infertile). This IMO is the biggest hurdle to finding breeding stock.

Yes it would be handy to be garanteed 3 females and 3 males out of a group of six. When it comes down to it though if you are serious about breeding a particular variety then you'd need to get a least six anyway (mortality, accounting for defects not seen at purchase age, bad parents, infurtility etc).

Sexing adult discus is pretty easy, and if you did get a lesbian pair you'd realise soon enough. Discus tend take a while to get it right when they are young so they'll waste time regardless. I know for me that once my pairs got it right I was still getting it wrong so the process takes time regardless.

Just my 2 cents.

[Ben]

Trebs, thanks for the feedback!
yes you are %100 right! they do take time to get it right! But i guess it help us (humans) get it right just that little bit quicker!

cheers,
Ben