in breeding in fish

[lynda orourke]

A fairly random thought occurred to me on the bus ride home, is in breeding a problem in fish?

I was thinking, you go into an aquarium shop and buy a few fish of the same breed at the same time they probably come from the same source and so could be related. Assuming the are a type that breeds readily you then end up with fry which you sell back to the shop, then some else comes in and dose exactly the same thing, you could end up with some very inbreed fish.

I know this can be a problem with mice, (you by two “females” and two weeks later you have 20 mice), and in mice I know it causes tumours.

have any of you had any problems with inbreed fish?

 

[Innovator]

I cannot remember exactly, but I believe genetic concerns are raised by the 4th or 8th generation and climb steadily from there on with tumors and body disfigurations apparent with fry. Someone call me on this as I don't remember specific numbers for certain.

 

[CatatonicBug]

I know it works in Silkworms, after several generations they start to have missing half-segments, so they look like they are bent one direction.

 

[thatmagicguy]

I think at this point we are seeing an industry wide problem in the fish stocks as a result of inbreeding and indiscriminate pairings of fish. In the old days breeders would be very careful to used separate lineages to produce superior fish, there was a competitive spirit among breeders to produce the biggest and prettiest fish. Those days, sadly, are gone. No longer are breeders infusing wild stock and building up genetic lines. Most of our fish will soon be coming from the far east where cheap labour and profit is the word of the day, rather than quality. And as long as we keep buying these inferior fish the market will stand.

I have been an open and loud advocate of the hobbyist breeder, and I continuously speak out against giving the breeder "store credit". Usually hobbist raised fish are far superior to milled fish from wholesalers and the hobbyist should be paid a fair wholesale price for their fish. It is nothing but profitable for everyone if stores buy fish from local breeders as opposed to wholesale establishments that refuse to provide the highest possible quality fish.

A store stands to profit because as the hobbyist is paid for their fish it cultivates an active interest to further their hobby and more tanks need to be bought and all the supplies and food etc.

Anyway, to answer your question, yes.

Bill

 

[lynda orourke]

Yes but

I agree big business and animal welfare don’t go together unless there are a lot of legalization and checks in place (why bother worrying about genetic lines if the fish sell anyway), but isn’t the amateur hobbyist likely to inbreed as well, though a lack of understanding of genetic diversity?

 

[thatmagicguy]

I think there is some truth to your concern at this point in the hobby's history. However, the store owner, in cultivating a hobbyist's interest in breeding for profit and for interest, can guide a hobbyist in selecting fish as breeders. Many fish, tetras come to mind, do not seem to suffer the consequences of inbreeding quickly, that is, we don't see deterioration in strains as much as we do in say,,,livebearers.

It has been demonstrated, at least here in the usa, that even in small markets, when demand from the wholesalers reduces, the wholesalers ears perk and they investigate quickly why there is a sudden drop in sales. I think that an aquarium society in a given area, that has an appreciable amount of members, can quickly develop a breeding program on a local level to supply stores in that area with most bread and butter fish. These fish, not faced with the careless rigors of being handled by the wholesalers will be much healthier and the retail outlets will see this quickly. This will have an adverse effect on sales at the wholesale level and they do indeed take notice. I have personally put in the past, a dent on dubious wholesalers here in my area by providing stores with the top 3-4 species that move and they have quickly investigated the drop in sales.

One obsticle we face here in the usa is the big box stores who are working hard to face the reality that customers quickly learn that quality counts. They still however, refuse to buy from local breeders for the most part. There are a few very small exceptions, but when buying decisions are made at a corporate level then quality always suffers.

Hope this helps. Bill

 

[kimo]

"They still however, refuse to buy from local breeders for the most part. There are a few very small exceptions, but when buying decisions are made at a corporate level then quality always suffers."

Ignorance is golden... as long as the bosses get their bonuses at the end of the year. Hit them up with a lawsuit (it IS illegal to sell diseased fish) and see how fast they change their tune...

 

[haykay]

huh..really? I had no idea it was actually illegal. I have a problem with this issue myself. as I have never bred any of my fish, but am concerned about my recent investment of live bearers.. If you have no fish clubs that you can find and no local breeders making themselves known how does one go about "purifying" strains?

 

[kimo]

huh..really? I had no idea it was actually illegal. I have a problem with this issue myself. as I have never bred any of my fish, but am concerned about my recent investment of live bearers.. If you have no fish clubs that you can find and no local breeders making themselves known how does one go about "purifying" strains?

Problem is: who is going to go to all the trouble (and cost) of small claims court, getting accurate and necessary PROOF of infection before purchase, etc.... over a $4.00 fish? The lfs owners know which tank is infected and the good ones at least isolate and treat them. Quality over quantity is the name of the game. Unfortunately some chain stores don't even bother to get the dead ones out, let alone treat any that are sick. Some hire people who are not knowledgable > OJT (on the job training) until after the fact.

"how does one go about "purifying" strains?"

I coud write a book about that one. A little knowledge of genetics helps, knowing the history of the fish you are breeding, keeping thorough and accurate records, knowing the difference between heterozygotic and homozygotic and how to change one to the other. Easiest way is to find the best pair of fish and go from there. Back cross, line cross, outcross are just some of the ways.

 

[black hills tj]

I became interested in breeding bristlenose pleco's about a year ago. Last summer I made sure to purchase 5 pleco's from different spawns. Unfortunately 2 of them died. However, as they grow near a year of age and sexual maturity, I have purchased 10 more from multiple strains. My hopes are to successfully spawn these fish and keep the bloodlines from crossing with each other to avoid aforementioned "inbreeding."

Once I can repeat successful spawns, I hope to distribute them both locally and nationally.

 

[kimo]

"My hopes are to successfully spawn these fish and keep the bloodlines from crossing with each other to avoid aforementioned "inbreeding.""

By keeping your strains seperated, you are really not avoiding "inbreeding", just the opposite.

 

[black hills tj]

I'm not keeping the strains separated. I have multiple tanks setup, and have a few different strains in each tank. I am making sure to avoid having a pair from the same spawn in any one tank.

 

[kimo]

"I'm not keeping the strains separated. I have multiple tanks setup, and have a few different strains in each tank. I am making sure to avoid having a pair from the same spawn in any one tank.

My hopes are to successfully spawn these fish and keep the bloodlines from crossing with each other to avoid aforementioned "inbreeding."
Once I can repeat successful spawns, I hope to distribute them both locally and nationally."

If you are not keeping the strains seperate, the bloodlines are mixing.
You will end up with all F1 heterozygots. You will have to breed brother/sister or mother/son-father/daughter to recover 1/4th of the color lines you now have (going back to homozygotic).

Much easier to use line breeding and then outcross strains every third > sixth generation to keep the line strong.

People who will be purchasing your fish will want to know their history, etc...
they will also be expecting that if they breed the fish that they will have the expectancy that the fish will look like the parents. Will not happen with a heterozygot (without further line breeding).

 

[black hills tj]

Can you give me an example of some sort Kimo? Maybe I am not understanding the line breeding and outcrossing correctly. It'd be best for me to straighten things out before my pleco's start spawning.

 

[haykay]

just a guess but I would think that Kimo is saying stay with the same pair (not related) for 6 spawnings and then either spawn the offspring to a different line or change out one of the parents.. I would guess that Kimo meant to breed the offspring to a different line though, but i could be very wrong.. Im reading this in snipits since im at work lol...

 

[kimo]

"Can you give me an example of some sort Kimo? Maybe I am not understanding the line breeding and outcrossing correctly. It'd be best for me to straighten things out before my pleco's start spawning."

just a guess but I would think that Kimo is saying stay with the same pair (not related) for 6 spawnings and then either spawn the offspring to a different line or change out one of the parents.. I would guess that Kimo meant to breed the offspring to a different line though, but i could be very wrong.. Im reading this in snipits since im at work lol...

What I'm trying to say is:

You have bought your initial fish (doesn't make any difference what kind... applies to all). you don't know the genetic history of the fish. The breeder you bought them from should know (private breeder) but not necessarily if all he is is an importer (commercial breeder). Sometimes you will get them all from the same spawn or line, sometimes not.
Line breeding involves taking the very best m/f fry, growing them, then breeding back (back cross) to mother/father or closely related uncle/aunt. Doing this over and over for 4 - 6 generations. Then using a fish of similar color finnage, etc but from an entirely different line breeding that into the next generation. Prevents degeneration of the line. All the fish (including culls) will be related somehow except for the outcross you just did. All fish born after this will be related in some way to the outcross. If you establish two seperate lines from the original parents (using a seperate and new outcross in each line) and keep these running indefinetly (homozygotic) but seperate... After a few generations you might be able to take a male from one line and breed it to a female from the other line to get an F1 hybrid (extra large, extra finnage (maybe), better color, etc). These (heterozygotic) will need extra breeding to make them "pure" again but may be good enough for show.
It involves very good record keeping and more than just a few tanks.
The minimum number of tanks just for one line in guppy breeding is 7. Usually you will end up with 3 lines going at any one time >> 22 tanks. (1 large one to hold all your culls that will be sold to the lfs (run of the mill fancy guppy or for feeders) After 10 or 15 years you might be good enough to show or sell them for $35.00 a trio. (what mine sold for in the '70's).
You also have to have the tank sized just right for your fry. Too small, they get stunted. Too large and the fry have trouble finding the food = extra grow out time. Then you have to allow for the times when the spawn is extra large and you have to find space for all of them. No buyers at a particular time = spare tanks needed >> SPACE for the tanks needed.

Back cross - breeding son/daughter back to parent to recover a certain gene.
outcross - bringing in a simular looking fish (outside the line) and crossing
into the line to prevent degeneration.
Line cross - Taking the very best of the fry (after they have grown some)
and breeding with parent for a few generations. The opposite
of back cross.
Inbreed (side cross) - breeding brother/sister to help recover, fix a certain
gene.

Come on over to guppies.com. There is a wealth of information on breeding that applies to just about any kind of fish.

 

[haykay]

aw.. i was way off! thanks for that very ionformational lesson in breeding!

 

[black hills tj]

Thank you very much Kimo. I just saved your quick breeding lesson into a notebad doc so I can refer to it at any time

 

[kimo]

"aw.. i was way off! thanks for that very ionformational lesson in breeding!

That's ok Haykay, and you're welcome ! It might not make that much difference in fish where the color or finnage is all the same no matter what. It's just that in Fancy guppies the large delta tail is the first thing to go if you cross unrelated strains. It ends up as a common "Boattail" in the next generation. BUT with a few tricks can be recovered.



"Thank you very much Kimo. I just saved your quick breeding lesson into a notebad doc so I can refer to it at any time"

You're welcome TJ. Just don't take it as "law"... only on general principles. There is a ton of info on the web now about genes, alleles, genomes, etc that weren't available (there was none!) back when I started in '68. It can get confusing in a hurry.