# Platy breeding/fry growout



## EBParks (Dec 22, 2010)

Our aquarium lab is starting a platy breeding program and I was looking for any advice that might be out there...

*Breeding tank: *My tank is 60 gallons, well planted. I was wondering what kind of male to female ratio I should have in the tank and about how many I should put in.
*
Fry tank:* I'm having a little trouble with the fry. I have a 10 gallon, heated tank, with a small sponge filter. There is a divider in the tank that is small enough for the fry to swim through. 

My plan was to have the pregnant females moved to the small tank, give birth, have the fry swim through the divider to escape a hungry mother, remove the mother, and have the fry begin their first few weeks there before being moved to a grow-out tank. The first batch of fry has not survived in the birth tank. 

I was hoping someone might have suggestions on temperature, filtration etc. for better fry survival or perhaps even a better way to do it like letting the fry stay in the breeding tank, among the plants until big enough to be netted out. Thanks!


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## navigator black (Jan 3, 2012)

Are you using wild stock maculatus for this project, or aquarium trade hybrids?

I breed a lot of livebearers, mostly Xiphophorus, and I never remove fry. If you want numbers, you will need more space than a 10. In a large enough tank (3 foot), cannibalism ceases to be an issue. You need a moderate current and hiding places for the first week or two. I use a rubble substrate - chunks of one or two inch rocks scattered all over the bottom. The fry go down, and cover is essential. I also have clumps of java moss along the back of the tank, other plants, and floating plants at the surface. I keep wild-types. and have built up large groups of variatus, montezumae, nezahualcoyotl, birchmanni and a few others using this set-up. I usually have to introduce a fry micropredator to keep the tanks from crashing due to overload.
For large groups though, I use forty long (4 foot) or 40 deep (3 foot) tanks. I have been able to build up small colonies of X evelynae in 24 inch 20 gallon tanks, but it's a lot harder and a much lower percentage of fry make it.

You can also cheat and use dollar store plant garlands. They seem designed for wreaths, and are a sharpish plastic. The parent fish don't want to go into the clumps, as I suspect it hurts. I will attach a bunch together in a corner (up to 1/3) of a tank. The fry go in and do fine. It's the trick I use for ferociously cannibalistic livebearers like Gambusia and Brachyrhaphis. I don't like leaving the cheap plastic in the tank, but the fry aren't hunted after about two weeks, and I have had no sex ratio issues with the plastic in the tanks. I don't see platys needing that heavy duty technique, but it depends on your resources. It would probably work in small tanks.

Ratios - one male to three females. In a sixty, I'd start with a dozen fish.

I don't heat, but the ambient temperature in the area where I have my tanks is about 20-21 c in winter (right beside a furnace and water heater). 

Hope that's helpful.


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## EBParks (Dec 22, 2010)

Thanks for all the info! I'll go ahead and deck out the main tank to be better suited to to hide fry and just stick with that. However I will need to eventually move the fry out, but it shouldn't be too hard to do do so after they are a little stonger and out of that "first two weeks" periond. Much appreciated!


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## Kevx (Dec 8, 2011)

I use a combination of larger planted tanks, and a classic v shaped birthing arrangement in a 10g tank, like in the old illustration below. This arrangement saves nearly ALL of the fry, as they fall free of the adult females, into a large roomy area below. The mommas are also comfortable in their own large area. You get maximum fry, and aren't left wondering if that really special specimen was eaten by a hungry tank mate.


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## navigator black (Jan 3, 2012)

That's an excellent technique above.

It's partly why I asked the original poster if he was keeping_ maculatus_ or platys. If you are breeding the hybrid colour varieties, you want every fry to survive so you can see if you get mutations or especially vibrantly coloured individuals to work with. In that case, I would use a trap.

If you are keeping the wild fish, then the no trap method is best, as you don't want the weaker, less nimble fry. I don't consciously select for any traits except the ability to survive, and I still end up with full tanks. I'm not a big seller of fish though, as wild types are not very popular. Were I a seller, I'd want maximum numbers.

The two postings show two approaches that aren't in conflict but are each trying to do something a little different.


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## Kevx (Dec 8, 2011)

navigator black said:


> The two postings show two approaches that aren't in conflict but are each trying to do something a little different.


I totally agree, Navigator Black. I use whichever method the current project calls for. I'm thinking of obtaining some Xiphophorus mayae wild-type swordtails, and I would definitely use a well planted tank for those.


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## navigator black (Jan 3, 2012)

I just lost my mayae, into the third generation. It's a big one that sexes out slower than any Xiphophorus I have ever kept - some males didn't develop gonopodiums until 13 months of age, and swords til after that. It is a nice and beautiful fish that needs a lot of room to run - I'd suggest a four footer.


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## Kevx (Dec 8, 2011)

navigator black said:


> I just lost my mayae, into the third generation. It's a big one that sexes out slower than any Xiphophorus I have ever kept - some males didn't develop gonopodiums until 13 months of age, and swords til after that. It is a nice and beautiful fish that needs a lot of room to run - I'd suggest a four footer.


Thanks for those tips. I'm intrigued by the size of these. I have a 55g that I would be using, so it sounds like it will be ideal. Ive read that they can be quite shy. Has that been your experience?


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## navigator black (Jan 3, 2012)

They were shy, but not crazily so. What was most odd was that they kept in tight shoals in their 65 gallon, four footer here. They swam as a unit, in a most unswordtail way. With their dark pink to red striping, it was pretty. 
I thought I had all females, then I thought I had one male and six females, but when the alpha siuddenly died, three more gonopodiums magically appeared.

I had about thirty going (and no longer shoaling) when I added some fish from a trusted source and shouldn't have - even quarantine woudn't have helped as the parasite they had takes six weeks to show. It wiped out the lot.

They were peaceful, but the alpha male did maintain his dominance and suppress development of the others, so things were aggressive on some level. They never came up to the glass and became tame, but they weren't skittish. I have some X clemenciae that just don't want to be seen - the mayae were nothing like that.


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