Brother/sister Crosses

[LauraFrog]

I'm just curious to know if anybody has done this before... I've been breeding platies for over 6 months, but the oldest are only just starting to come into sexual maturity. I'm intending to give them away... the ones that I'm keeping are very young, born this week.

I have two strains that I'm working on, copperblack and pied. My best females have taken to dropping both strains. I have only 1 fry tank which is very small, and over 300 fry. Most of them are in plastic containers outside... the majority of them live but the survival rate is better for the ones hand-raised in the fry tank. So. If I put them in the fry tank, I will have to mix the fry and I can't separate them by mother. I won't know, with the mature fry, whether I'm making a brother-sister cross or not. I know loads of people do cross brother and sister fry - will this damage the strain? The fry probably all have the same father anyway and I don't know whether some of the parents are closely related, so there is going to be some inbreeding. Is it worth making any attempt at all to minimise it?

 

[luque]

buy a new tank?
if you want to keep the strains, personally i would't cross them.
and IMO don't inbreed them as i beleive there can be birth defects

 

[LauraFrog]

buy a new tank?
if you want to keep the strains, personally i would't cross them.
and IMO don't inbreed them as i beleive there can be birth defects

My father has spoken. No more fish tanks.
I'm not intending to cross the strains, but my females are dropping both and then I'm going to try to cement them.
They're already inbred. I'm still thinking on how I can separate them.

 

[fish48]

crossing brother and sister will do verry little damage i bred all my fish this way in other words i leve them to flock breed. i have kept some strans of fish for many years with no effects however care must be taking to remove any fish that may be deformd or that dont swim or look right. ony breed with the the best. adding new blood would be the best option but it is not always possible.

 

[kribensis12]

crossing brother and sister will do verry little damage i bred all my fish this way in other words i leve them to flock breed. i have kept some strans of fish for many years with no effects however care must be taking to remove any fish that may be deformd or that dont swim or look right. ony breed with the the best. adding new blood would be the best option but it is not always possible.

Well siad, but inbreeding does have more serious effect's.

 

[Mikaila31]

Inbreeding every now and then won't cause problems. It once you start inbreeding for 5 or 6 generation that you will start to get problems. Any chance you could set a large plastic tub outside and raise the fry there?

 

[dortiz24]

What about buying dividers and putting them in the tank? That way you have a sectioned fry tank....a sections for each mothers fry. Maybe that would work. go to www.aquariumguys.com...they have pretty cheap dividers, various sizes and I believe you can also cut them to size.

I don't know about brother/sister breeding but I hope that idea helps.

Godd luck.

 

[LauraFrog]

Inbreeding every now and then won't cause problems. It once you start inbreeding for 5 or 6 generation that you will start to get problems. Any chance you could set a large plastic tub outside and raise the fry there?

The 'large plastic tub' is basically what I'm doing, I have several set up. But I have no way of filtering, heating or aerating them. The temperature is suitable - 24-25 degrees - but not always constant, stuff gets blown in and lands in the water. The vast majority of them live, but when working with rare strains, where less than 25% of a drop is currently carrying the traits I want (first generation fry, it isn't breeding true) I don't want to take the risk. I did move them inside because a storm blew up and I got overprotective again.

The fish I have to use as parents at the moment are from the pet shop. There's only one that's perfectly marked, so I look for other fish with similar markings or patches of the colour I want (which is common) and cross them in - so far it's working, a fish with only a hint of the copperblack pattern just threw 7 true copperblack fry (in a drop of over 60, but still!) They do show up, but I have never seen them anywhere else (internet included) and the supply is inconsistent to say the least - I snap up what I can get but I think I'm going to have to rely on the fry. It doesn't seem to be a very common strain.

I do cull anything that's deformed. Up to about a week after they are born I feed them back to the parents, so taildraggers, twisted or 'corkscrew' bodies or ones that never uncoil, they just get put back in the fish tank. I also cull out the ones that don't grow properly, the ones that don't grow as fast or that retain that 'hollow sides' look no matter how much they're fed. I'm selecting for size and vigour as well. I would prefer to work with that after the colour is cemented, but I won't choose weak, sickly fish as breeding stock - that's stupidity.

I have thought about dividers... it's a very good idea, but impractical for my fry tank because it is hexagonal, and also because the filter current is quite strong. The fry are tossed around in it and shelter in corners - if I divide the tank, they won't have anywhere to hide because the decorations won't fit. I have tried to divide larger containers with little success because I tried to do it with muslin weighted with rocks. My parents won't let me buy anything over the internet.
Do these dividers allow water flow but not newborn fry to swim through?

 

[Mikaila31]

I would work with the tubs outside and see how well you can get them working. I am very excited for summer to role round, as I'm going to be experimenting with tubs outside as well. Start with fish that you feel safe risking, then once you get a system going try it with the more important strains. You could keep the adults inside and move their fry outside to the tubs. Here is a article that I am going by for my tubs. It is about the 18th page down. It sounds like a easy way to breed and raise fish.

 

[Tokis-Phoenix]

Inbreeding with livebearers is something you should avoid at all costs, inbreeding has already seriously weakened guppys as a species and now platys are looking to go that way too- inbreeding has weakened guppys in so many ways, inbreeding makes guppys grow smaller, have weaker imune systems, males have more feminine shape, guppys are more likely to die from unexplainable sudden death syndrome, defects/mutations more common, fry survival rates are poorer, fry growth rates and max adult sizes are smaller, guppys don't live as long in general, female guppys are less likely to cope well with pregnancy and labor/birth etc.

If you are already getting numerous birth defects with the fry then this is a bad sign that your platys are already pretty inbred (too inbred IMHO), as you said yourself;

"I do cull anything that's deformed. Up to about a week after they are born I feed them back to the parents, so taildraggers, twisted or 'corkscrew' bodies or ones that never uncoil, they just get put back in the fish tank. I also cull out the ones that don't grow properly, the ones that don't grow as fast or that retain that 'hollow sides' look no matter how much they're fed. I'm selecting for size and vigour as well. I would prefer to work with that after the colour is cemented, but I won't choose weak, sickly fish as breeding stock - that's stupidity."


You really need to do something about all the inbreeding in your platys and the problems concerning over-crowding (which does sound like it is the case with you). You should separate your adult males from the females so that the females eventually stop getting pregnant, and you should keep a closer eye on the development of your platy fry, as there are signs to look out for with juvenile platys which can allow you to accurately guess which platys which mature into males before they actually fully mature so you can separate them from their sisters before they do mature and then inbred with their siblings etc.

Also, have you considered rehoming a certain percentage of your juvenile and adult guppys? If you don't have the right space for them all, you should really start seriously looking at the rehoming route to help cut down on the fishes numbers to more manageable levels .

 

[helterskelter]

crossing brother and sister will do verry little damage i bred all my fish this way in other words i leve them to flock breed. i have kept some strans of fish for many years with no effects however care must be taking to remove any fish that may be deformd or that dont swim or look right. ony breed with the the best. adding new blood would be the best option but it is not always possible.

I back Fish48 all the way here

Crossing it not a problem this is how all the different lines of cultavated fish have been devloped by back crossing and this has already been done for many years with little problems.

Ok they may not be as hardy as wild fish but thats not bad thing, as long as they are happy in the aquaria.

 

[Butch]

Well you can use half brother, half sister breeding instead of full brothers/sisters breeding till you find another unrelated strains which isn't easy to find. However platy are actually hardier than guppies IMO. And record on the platies' history and strains etc.

 

[Tokis-Phoenix]

crossing brother and sister will do verry little damage i bred all my fish this way in other words i leve them to flock breed. i have kept some strans of fish for many years with no effects however care must be taking to remove any fish that may be deformd or that dont swim or look right. ony breed with the the best. adding new blood would be the best option but it is not always possible.

I back Fish48 all the way here

Crossing it not a problem this is how all the different lines of cultavated fish have been devloped by back crossing and this has already been done for many years with little problems.

Ok they may not be as hardy as wild fish but thats not bad thing, as long as they are happy in the aquaria.

Inbreeding is actually causing a lot of problems, its mostly affected guppys but it is affecting platys now days too, guppys and platys are no way near as hardy as they used to be in the past and it is all down to too much inbreeding.


This person seems to be trying to actually breed better strains of platys but it sounds like their platys are already ready rather inbred, i never ever get birth defects in my platys and the only ones which are smaller than average are ones i've either bought or have been given, because i take take great care to ensure my platys do not become inbred etc. I find it rather worrying that this person is culling fry on a regular basis with new batches because of birth defects.

I would advise this person to halt or seriously sort out their breeding program as they obviously do not have the space to raise the 300 or so fry they currently apparently have- you can't raise good quality platys if you don't have good conditions which are not overstocked.
Breeding platys in a serious and intentional manner means that you need to have the space and money to do it to afford all the right size tanks for the fry etc, good intentions are not enough. I don't personally think its good to knowingly breed very inbred fish, you can't really say that you're "improving" the species if you do this.

 

[stiffler69]

I currently get no defects in my platys i have large batchs of fry 35 been the smallest and all the way upto 60-70 and dont loose any the fish are as beautiful as its parents, i currently have 6 females and i am a little top heavy on males at a count of 3. I purchased my fish from different stores so all the females came from my more local store and then the males came from larger outlets such as mainhead etc. As soon as the fry are born they are allowed to grow out in the net for 2 weeks and they are then transfered to a 56 litre fry tank just for fry, i dont let numbers get above 150 in this tank although whilst they are small there is lots of room for them, i do realise this is too many and sell them on at a age of 5-6 weeks just as they become large enough to go it on there own in a community tank. When i sell the fish on i give the buyer a selection of fry from each individual female what gives them more chance of having less interbred fish.

Without massive amounts of tanks and a very good routine of seperating males and females i dont think there is alot a person can do about this interbreeding. I do my best to seperate them from the parents and try and give a selection of juveniles from each individual female but this is all i can do.

 

[Tokis-Phoenix]

Without massive amounts of tanks and a very good routine of seperating males and females i dont think there is alot a person can do about this interbreeding. I do my best to seperate them from the parents and try and give a selection of juveniles from each individual female but this is all i can do.

Your situation sounds a lot better than LauraFrogs though, at least you are getting physically healthy batches of fry, which is always a good sign. Its when people start regularly getting very weak batches of fry or fry with deformities then its time to really seriously do something about sorting out the inbreeding- i agree, its difficult to prevent all inbreeding between fry, but the main thing is to try and do your best to avoid it. I just primarily disagree with some of the other comments said on this thread here which seem to brush off the matter of inbreeding as no worry, when really it is actually a very important thing to know about when breeding livebearersetc .


If you have a pet shop willing to take or buy platys off you then that always makes things a great deal easier because it means that you won't need to keep large numbers of related males or females or have to ste up loads of tanks etc. A small amount of inbreeding between platys that are not very closely related is usually no problem at all, its just a problem when already very inbred platys continuously inbreed with each other every generation that the situation becomes bad.
Introducing fresh gene's into your livebearers gene pools by doing something like separating all your males from your females and keeping the males in an all male tank while buying a brand new male completely unrelated to all your current platys and letting him and him only mate with your female platys will help them produce much more genetically stronger fry than the fry you'd get out of your home bred males which are related to your home bred females- you can then just rehome the male after a year or so and buy a new one, so that large percentages of your fry that you decide to keep do not share the same father so at least if you do decide to breed your home bred platys with each other, you have a more genetically diverse group of platys to choose from .