Larger fish..bred smaller?

[JamisonBWolsh]

************************************
Disclaimer on bottom
************************************
A point came out in one thread that stated large fish are good for large tanks. I Just dont think this is fair. Why cant I keep a tiger shovelnose in a 50 gallon? or larger fish in smaller tanks?
Its just not Fair (yea..lifes not fair)

An Idea:

We can breed colors in fish. We can breed certain chararistics (mispelled) in fish. I wonder, Is there ANY way to breed fish to grow smaller? Like max at 10 inches instead at 4 feet? That would allow EVERYONE access to fish that only certain poeple with Large tanks have....

Maybe saving the runts (the once smaller then the rest) in a breeding group and breed the runts togethor? Yes. its unnatural..but keeping fish in a tank is unnatural. By maxxing out Oscars at 4 inches, one can keep several in a 55 gallon tank. I think This idea can change the fish keeping industry.

Can it be Done?

*******************************************
Disclaimer: This is an honest question. No flames please. No rudeness will be tolerated. If you dont like the topic..dont read it. Thank you.
*************************************************

[Serrateeth_2002]

That's not a effective husbandary technique because genetics works in fish are similar to humans,example,2 short parents a short father,a short mother may get a tall son,same with fishes,but as i said before,all what i said is i thought of.

[JamisonBWolsh]

Makes sense. I just thought this idea would bring alot more to the fish hobby.

[Tom Griffin]

a runt is a genetic malformation. its size is usually a visual manifestation of problems that are likely much more severe under the surface.

To develop a strain of a specie that is significantly smaller woudl require an extended time frame with coinsistant conditions that favor smaller specemins...and at the point you produced consistantly smaller specemins, without the return to the natural size...you woud essentially be creating a new species.

Somethign that in the framework of geological time is easy enough...but for the length of time you are gonna be keeping fish...I seriously doubt you are gonna evolve out a new species...

unless you breed for genetic deformations.

then you are simply wrong....

[Serrateeth_2002]

i thought runt was referring to a small individual which lacks growth hormones but Tom Griffin said it was a mutant,in that case,it is not possible because mutants are sometimes infertile or not a good mate for females that choose the mates.

[JamisonBWolsh]

would it be hard for a scientist (not me of course) to mess with that specific dna strain that controls size of a fish? If they can..would it even be profitable?

If they can make GLOW in the Dark fish (which they did)........I wonder what they can do about size.....

In the end though, probably wont be profitable to experiment and finally get that fish, then breed them in the millions for shipment throughout the world.

Also, remembering about the genetically modified corn (where countries REFUSED to feed their starving people with in fear of mutating with the corn they grow). Oh wait. whats the chances of a genetically created oscar (to grow smaller) to escape to the wild where their natural habitat is and breed, forever changing that species? Not a big chance......Its an Idea though.

[Serrateeth_2002]

maybe they just rationed the growth hormone out of the pituary glands.

[Argento13]

They have done this with chickens, Bantams are a "midget" breed of a standard sized chicken. How long this took i do not know but some breeds of Bantams have been around for hundreds of years.

[JamisonBWolsh]

really? if it was done a hundreds of years ago, I wonder how they did that? No dna splicing in that timeframe.

[Qsmon]

Survival of the Weakest?!??!
I think most tropical that have been kept in tanks have already shrank in size as compared with their wild counterparts generations removed.

[keely]

Of course it can be done. Dwarfing species has been done with everything from birds to ponies to dogs to... well, whatever. Size is a trait that can be bred for selectively like any other. I'm sure it's already being done to fish by someone, somewhere.

I don't think there is profit in it. People just take their fish back to the store when they get large, or continue keeping them in a tank that's too small. Or the fish's growth is stunted by tank conditions, or dies before reaching maturity. Look how big bala sharks and tinfoils and oscars get, look how few people have an appropriately sized tank, and yet look how many are sold in every LFS on the planet. I don't see how dwarfing them would increase sales by much.

[JeffP]

As Keely said, It can be done. Size is one trait just like color, fin shape, body shape, etc. All critters (including people) have a genotype based on genetics and a phenotype which is the physical expression of the genetics (i.e., how we look and act).

Although I am not a breeder, developing variations within a species is more complicated than taking two small parent fish. The technique usually used is called line breeding. This is where parents are bred with selected offspring, selected siblings are bred to each other, etc. This process is repeated over and over again. Every now-and-again, an "outside" fish may be introduced because it has a trait (small size, fin shape, etc.) and the breeder wants to introduce its genetics to his line. I understand that this has to be done carefully.

Anyway, line breeding has the effect of decreasing genetic variability so that the breeder can get more consistent results (e.g., smaller fish) than by randomly breeding parent fish who are small.

Gene splicing is a different animal altogether and is not to my knowledge used in the breeding of fish. My sister is a molecular microbiologist and routinely takes dna from one critter and puts it into a new critter....usually to see if she can get the new critter to do something productive like make (or breakdown) specific chemical compounds. Could it be used to "speed up" the line breeding process? I don't know.