I know nothing about this as I am a first time Platy owner as of about 3 1/2 weeks ago. That said, reading your post makes me question, why you don't just allow all the fry in the tank with the adults as they are doing better that way anyhow and you won't have to work so hard to do it? Just curious, not judging.

 

I net them because most of what I leave in the tank gets eaten. I guess it's a "strongest will survive" thing going on, because the ones that make it to adulthood are the healthiest and most colourful.

I also try to make a profit from them. I never need to buy fish food anymore; if I need any food, I just bring in 5 or 6 fry to my LFS and I get it for free. It's been nearly a year since I bought fish supplies

 

I net them because most of what I leave in the tank gets eaten. I guess it's a "strongest will survive" thing going on, because the ones that make it to adulthood are the healthiest and most colourful.

I also try to make a profit from them. I never need to buy fish food anymore; if I need any food, I just bring in 5 or 6 fry to my LFS and I get it for free. It's been nearly a year since I bought fish supplies

It is for this reason that I thought it might be fun to give it a try. Not sure how it will go if it happens at all as I only have the one tank and not intending to get big into breeding but it would be nice to get a bit of store credit for a change instead of always spending more.

 

I have a problem with raising livebearers. Whenever my platies/swords have fry, I catch the majority of them and always purposely leave a few in the tank to fend on their own. I always notice the ones that I leave in the open with the adult fish grow faster and larger than the ones I raise in the breeding net.

I have a 2.5 inch long male that grew up in the tank who is only 2 months old, while I have a half-inch fry which was raised in the breeding trap who is nearly 12 months old. Same goes for ALL fry I catch and raise in the net.

What am I doing wrong? My month old batch is already doing the same. The fry I left out in the tank are already big enough to eat from the surface without hiding from the adults while the ones in the net are quite small.

I feed the netted fish 4 to 8 times a day and I give a good mix of food. I use hardboiled egg yolk, ground up betta food, soft spirulina pellets (their staple), ground up hikari veggie flakes, and a few others. The fish in the net get much more attention and variety than the adults do. Most of my net-raised fry only grow to a very max of 1.5 inches. I have a giant of a female who is nearly 4 inches long as well, but it was not raised in the net. My friend said it could be due to a lack of oxygen flow for the fry.

Are you introducing new females and or males or are the fishes all from one or two parents?

 

I sometimes go out and buy 2-3 more females from a different LFS (to get different genes than the one I trade with). That being said, someone I know gave me 15 of their own fry a few months ago (which grew just fine). I have good diversity. Some of my fry are even hybridized with swordtails (they grew large).

 

I think it's probably environmetal.

Are there different lighting levels? Light plays an important part in fry development.

What is the feeding regime like? It's possible the fish in the tank are able to browse constantly as livebearers generally do.

 

Different lighting levels? Only on or off

I feed them 4 to 8 times throughout the day between 8 AM and 12 AM. I never feed them less than 4 times. Since I woke up (it's 1:20 here right now) I've already fed them thrice; I keep a close eye on them.

 

I used to put my guppy fry in a breeder box. Then I started just letting them stay in the main tank. I found that the ones left in the main tank grew faster, bigger and stronger than the ones in the breeder box. I believe it's because they get stronger from having more swimming room. They get more "exercise" if you get my drift. If you have plenty of plants and rocks most of the fry can evade the adults. They will get thinned out but that's a good thing because you don't want your tank overrun with too many fish.

 

My fish are now at a size where I think it should be safe to let them loose. I might try that, I was thinking that might be the case too.

Seems like you had the same results as I did.

 

Oh, no. The light is the same. It's a 25 gallon tank, not too big.

I was thinking you meant one of those awesome lights where you can change settings... forget what they're called.

 

Is the temperature the same? Fry grow faster the warmer the water.

If you want to continue removing fry from the main tank, then turn up the filter (or use a larger one) to create water movement...
(Will act like a 'treatmill')

 

There were 15 fry in the net. I just removed 4 of them and let them go free.

They were way too used to protection, and nearly got eaten by the adults. They quickly hid away in the moss (java moss EVERYWHERE in the tank).

Hopefully they'll live.

I raised the temperature bit by bit over the last 2 weeks. It *was* 22 celcius, today it's 27.

 

None of the above seem exactly correct.

The reason why some fry grow fast and the others slow is because fry release a growth stunt hormone into the water they are in. Some of the bigger ones release more into the water resulting in the rest being stunted.

The simple solution is 50 - 60% water changes with aged water. You can ask many Angelfish and Discus breeders about this. This dilutes the stunt hormones making them weaker and useless.

This goes for bettas, gouramis and most,if not all, freshwater fish.

Tank size is important. Light plays no role in fish growth whatsoever but is important nevertheless.

Growing fry in green water should prove beneficial!

Regards

TankMaster

 

Please consider the science behind growth.

 

Hello. I too have noticed the same thing. I think it may well be a matter of available space. I had some swordtail fry that I kept in a net breeder while one was swimming free. The free swimmer is now an adult, the two in the net never did seem to grow so I finally released them into the tank. Unfortunately, I never saw them again.
Currently, I have about 20 molly fry in a 5 gallon tank. Most are going to the oscar, but I do have a home for 3 of them when they get big enough. All the fry were born at the same time, but some are bigger than others. I think in the interest of surval of the fittest, the oscar will get the small fry.

 

I used to breed Angelfish and what you're saying is very true, frequent water changes are vital to good, even growth across the brood. That doesn't explain why one batch will grow more slowly that another batch in the same water though.

I don't have any experience experimenting with light levels and growth but that was the advice given from an experienced livebearer breeder.

 

Maybe 1 batch had weaker growth stunting hormones? This is what I see it to be.:lol:

 

I see two of the four fry I release swimming around, but not the other two. They might be hiding, but I hope I didn't send them to their death!

 

Update to this.

Judging by the date of my last post, it's been nearly 2 months since I let the fry go free. They're still not very big at all and have not developed full colour. They are roughly 3 months old I assume.

- I changed their diet a bit to put more of a stress on protein, but it doesn't seem to be working much.
- I changed the tank's environment to allow for more swim space (which they love)

Ideas? They're still small.

 

Update to this.

Judging by the date of my last post, it's been nearly 2 months since I let the fry go free. They're still not very big at all and have not developed full colour. They are roughly 3 months old I assume.

- I changed their diet a bit to put more of a stress on protein, but it doesn't seem to be working much.
- I changed the tank's environment to allow for more swim space (which they love)

Ideas? They're still small.

New females and new male(s) would introduce new genes and possibly larger fish assuming large female's and or male's were chosen
Many times the fishes offered are all from the same spawn and as such , they may or may not have the genes for growth desired.
If after this time growth was still slow or fishes were small,I would be looking for new breeding stock.

 

I found that out a long time ago, Fry left with the adults grow bigger and better then the ones removed,
Mollies NEVER do good in separate small containers, especially birthing netting or traps, Alot of folks can't even get them to live in those things past a few weeks let alone longer, So I'm not surprised their smaller.. more surprised their still alive.

As for the growth hormone, I totally do not believe that,

We seem to harbor and cater to the weaker fish, trying to save everything, So we look to blame it's faults and troubles to everything but what it is, in the wild these weaker, stunted, smaller sickly fish would never have made it to adult hood let alone to reproduce, Fish are bred for the numbers not their hardiness, it's all about profit.

I use to try and save every fish no matter what, But all you do is keep bringing troubles on yourself,
I got really tired of it and started culling extremely heavily. here's a good article on this, it also states

"Fish are kept incredibly overcrowded in ratios of up to 200 per 10 gallon, growing to very good size, shedding considerable doubt on the theories surrounding release of growth-inhibiting hormones in crowded conditions."

http://www.fancyguppies.co.uk/page68.htm

 

Try live foods...

I'm feeding some of my fry on BBS and they seem to be growing faster.

 

I will try live foods eventually.. my location isn't the best right now considering how far I need to go to get to a store.

I've been feeding the fry a lot more egg yolk lately and less veggie-based foods. I noticed a small growth spurt in the younger ones over the last few days. Maybe my luck has changed

 

I personally don't use breeding nets... I have a moderately planted tank. Mixture of java moss, java ferns, other and several other plants, ranging in size. About 1/4 of my plants float around as I allow them to attach to other objects and grow. I'm referring to my 110 gal tank right now. Nothing but Livebearers (guppies, mollies, platys, swordtails) and one pleco... and snails...

Anyways, Fry popping out all the time. I don't feel the need to save any fish that dies. It died for a reason. Just like older fish die for other reasons. I rarely have adult fish that die of anything but old age. Younger fish I don't keep track of them just because of the volume I see. I'm also constantly adding to the breeding pool and removing other males out of the stock. I cycle through males however keeping the females. Due to m/f ratio is usually 1:2, 1:3, and even 1:4 ratio's. I have a secondary tank Smaller size, that I keep males in, no females. This tank is to cycle through males back and forth or give them away to other people (usually I sell them).

I'm trying to create some hybrid fish species that are colorful and can reproduce within the new hybrid species. My 110gallon tank is a free for all. no limits no singling out. However I'll be starting another project to single out species to breed with other species. I'll be documenting this section in detail.



Anyways, my rule of thumb is breeding nets are used to keep males from females until another house can be found. I generally only used them in breeding betta's. Other than that keep it more natural with survival of the fittest.

 

I usually only rescue a few in the breeder net and let them go free once they're a bit big (2 weeks to a month). I feed them a lot during that time.

It's only a 25 gallon tank though. And yeah, I use a *lot* of java moss for cover which is why I get a lot of living fry.

I just wish I had a bit more room. I'm not getting as many offspring as I used to either. I probably need to unload a bunch and start being a bit more strict with the genetics

 

As for bigger tanks, I started with 10's, then went to 15's. Lucked out and got a steal on a 55g full setup. 4 years later (this year) lucked out on 2 more 55's just tanks though. Then a week later a 110g. I own over 10 aquariums.

As for you, being strict about your genetics is important. But remember only in good fun. Don't stress over it, and only do it for the fun of it. You probably can talk with your LFS and say I'll give you 3 for 1. However most pet stores will only take platy's for example once they are about 1" in size.

I generally do this. I go to my LFS every so often with 50+ full grown adults. In exchange I get drift wood, more species of fish / males... etc... he orders specific breeds for me when I ask. This is helpful to me, however not all LFS will do this. But most will, as long as it's not a chain store such as Meijer, Walmart, Petsmart... etc.


I don't know your living conditions or how much extra room you have, or money for that matter. Depending where you live, check Craigslist for aquariums that are dirt cheap, full setups... like 10gallons... and raise some young in it to sell to the LFS. Depending you can make your money back off of it later. I don't pay for fish food or anything... ever... lol.

 

If you go online you can order cultures...
microworms and banana worms are good easy cultures...

I plan on switching to them when I run out of BBS.

 

If you go online you can order cultures...
microworms and banana worms are good easy cultures...

I plan on switching to them when I run out of BBS.

Yes,, microworms and other meaty foods can be offered but do not forget that livebearer's need substantial algae ,and or spirulina flake for they are largely herbivores in the wild and feed on algae,plant matter,and the tiny infusoria that are found there.
I used to throw a hunk of java moss in with the fry and also fed crushed formula II by Ocean Nutrition as staple part of their diets and the tiny fry did well.
Dried marine algae hung in the tank with veggie clip ,will quickly dissappear in a tank full of livebearer's.
I offered freezedried blood worms and spirulina brine shrimp as treats perhaps twice a week for adult livebearer's.