# is inbreeding a plroblem with fish?



## Wiley (Jan 19, 2009)

i have two fish that are possibly from the same parents.... is inbreeding an issue with fish? they are African Daffodil Brichardi (Neolamprologus pulcher).


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## BioG (Oct 12, 2008)

inbreeding is a problem if you're re-breeding. Genetics are the same in fish, relatively speaking, as people. You will find fish with good traits even though their parents are bro-sis but that doesn't make them genetically dissimilar.

You can either cull (kill) the defective looking fish ( you will miss some that have invisible flaws i.e. kidney probs etc.) hoping to create your own diverse stock after a few generations. 
in Florida however, cichlid breeders are abundant so I would just try to locate unrelated parents. If you're not selling the fry than it, of course doesn't matter.


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## Fogelhund (Dec 3, 2002)

Is this just a hypothetical question, or are there some issues with the fry?


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## Number6 (Mar 13, 2003)

Wiley said:


> i have two fish that are possibly from the same parents.... is inbreeding an issue with fish? they are African Daffodil Brichardi (Neolamprologus pulcher).


Inbreeding depression is real, but largely misunderstood. Breeding fish with bad genes is the real problem, inbreeding just amplifies/ speeds up what we see happening.

As Fogelhund asks, what issue are you having with the Daffodils?


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## Wiley (Jan 19, 2009)

i bought two brichardis and the fish guy at my LFS said he knew the breeder personally, and he gave me two that he thought may be a male and a female.. i didnt think to ask him if they were from the same parents or not.


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## Fogelhund (Dec 3, 2002)

Wiley said:


> i bought two brichardis and the fish guy at my LFS said he knew the breeder personally, and he gave me two that he thought may be a male and a female.. i didnt think to ask him if they were from the same parents or not.


They _should_ be fine as long as the fry in the tank at the LFS were all fine. Inbreeding issues can take MANY generations of inbreeding to manifest itself, if the original stock is free from genetic issues. At least in my experiences.


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## BioG (Oct 12, 2008)

I'm with number6 on the biological specifics. Bad genes collide at a greater chance rate when you double up on them but you should be ok as long as you watch for traits which are unnatural. I.E. spine twisting, mouth twists or deformities, gill plate deformities and fin deformities are most common.


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## Wiley (Jan 19, 2009)

BioG said:


> I'm with number6 on the biological specifics. Bad genes collide at a greater chance rate when you double up on them but you should be ok as long as you watch for traits which are unnatural. I.E. spine twisting, mouth twists or deformities, gill plate deformities and fin deformities are most common.


now that you say deformitives like mouth twists... i actually have a baby Boreyli that has a bit of a crooked mouth.. that a definite sign of inbreeding?


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## BioG (Oct 12, 2008)

could be. Look closely to see if you can discern if it was an injury (there would be bulging or scarring where an injury was healed), if not there is a good chance inbreeding may have accelerated a bad gene.


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## Fogelhund (Dec 3, 2002)

I would be concerned about a mouth twist too. The other possibility is that somehow it was an injury sustained during mouthbrooding. If you continue to see deformities such as this in other fry, it should be a sign to cease breeding these fish.


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## Dave (Feb 9, 2003)

Deformities of the mouth can be caused by injury during development, poor water quality, low mineral content in the water, or genetics. I personally avoid breeding fish that have mouths that are not formed properly, but I have done this in the past. In the one case where this occurred in my tank, the fry had perfectly formed mouths. This was a mating of siblings from the same spawn where the male's mouth was not shaped correctly and there was a slight bend to the face. I no longer breed these fish, and the spawning was not intentional.

What was the reason for the deformity? I don't know. I guess my point is that it could take many spawns and crossings to figure out if the deformity is genetic or not. I would rather not deal with this unless the species is very rare.


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## caseyof99 (Aug 5, 2009)

I had an electric blue ahli that i called rambo because his mouth was damaged while he was young and left cocked to one side a little. You couldnt see any scaring or any signs of damage after about a week of this happening. I think he thought he was bigger than he was and lip locked with a much bigger fish breaking his jaw a little. Didn't affect his eating or even eventual mating but if i bought him after that happened i would swear it was a deformity not injury.


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## 24Tropheus (Jun 21, 2006)

I think the problem with breeding siblings is we do not have enough data to say weather you are likely to have problems or not. (may vary from species to species and population to population (collection site) and how many generations they have already been inbred for) It is I think good practice to avoid sibling mating but in the "real world" I am not sure many folk bother.

For example if a line suffers from a genetic mouth twist out breeding may well give many carriers but few sufferers. Inbreeding with culling, over a lot of generations, you may be able to rid yourself of the trait and the mutant genes responsible. Swings and roundabouts?


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## Number6 (Mar 13, 2003)

24Tropheus said:


> (may vary from species to species and population to population (collection site) and how many generations they have already been inbred for) It is I think good practice to avoid sibling mating but in the "real world" I am not sure many folk bother.


It does matter what species, and that is a very well known fact. E.g. shell dwellers... inbreeding of any kind will result in a greater percentage of odd or deformed fry due to them being a naturally outcrossing species (hybridization noted in the lake due to shell stealing).

Personally, I like to allow breeders to form out of as large a group of fish as possible (related or not- let the fish decide) and when I've done this, some half sibling pairs have formed with no increase in deformities. This has held true over many generations as well...


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## 24Tropheus (Jun 21, 2006)

Nice point. On the species in question (pulcher daffodil) I can only give one example with a friends fish. He got 3 from a breeder at auction so prob siblings. One had a mouth twist. They formed a "pair and a spare" we think the two normals bred together with the mouth twist guy helping raise the young but that is partly conjecture the spare mouth twist guy may have been involved in some of the spawning unseen. He got about 1/4 of the young with a mouth twist.
It might have been interesting to carry on the breeding but he just dumped the line and started again with fish closer to wild and some unrelated ones not wanting to have to cull or keep and breed deformed fish.


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## Number6 (Mar 13, 2003)

*24Tropheus*
a wise move IMHO. Of course, there is such a thing as too much of a good thing... his plan of getting fish from two sources is wise IF he got a large group of each... if he bought one or two from those 2 different sources, then he's fallen into a counter problem of random outcrossing... just as incorrect an approach in my experience finding quality breeder cichlids.


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## 24Tropheus (Jun 21, 2006)

Can you explain why it is good to give the fish a choice rather than force out breeding?
I am not sure its random in his case because he selected two lines that seemed to show good colour and few breeding problems (as far as you can tell just by asking the breeder and looking at the fish in shops).

To be honest I have often found it a little annoying giving the fish a choice of unrelated and related mates and then them select sibling partners to breed with. Is this a natural and normal thing for them to do and in some way good for the line?


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## Number6 (Mar 13, 2003)

I'll let Darkside continue portions of our conversation in the Tang section... 


24Tropheus said:


> Can you explain why it is good to give the fish a choice rather than force out breeding?


 I can only take an educated guess but I would suggest that the fish use visual and behavioral cues to determine health/fitness and are attracted to that because of the evolutionary success that approach has brought the species.



24Tropheus said:


> I am not sure its random in his case because he selected two lines that seemed to show good colour and few breeding problems (as far as you can tell just by asking the breeder and looking at the fish in shops).


 IMHO, it is random from the fishes perspective, though from our perspective, the word "artificially" might be appropriate.



24Tropheus said:


> To be honest I have often found it a little annoying giving the fish a choice of unrelated and related mates and then them select sibling partners to breed with. Is this a natural and normal thing for them to do and in some way good for the line?


There are theories... one is the "Selfish gene theory" but I wonder if we aren't overcomplicating it a bit. Really, life is all about balance of forces and for the fish to have a balance of sameness vs differences, there must be individuals at both ends of the spectrum... some fish will lean towards picking "that which is similar" and others will be attracted to "that which is different".


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## 24Tropheus (Jun 21, 2006)

Thanks  
I came across these.

http://www.ingentaconnect.com/search/ar ... 20&index=7
http://www.ingentaconnect.com/search/ar ... 20&index=3
http://www.ingentaconnect.com/search/ar ... 20&index=6
Might be of interest but slightly off topic I am afraid but interesting about their breeding I think.

PS
Very familiar with "Selfish gene theory" and its explanation of apparently altruistic acts and breeding strategies in animals. :wink:


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