Survival Of The Fittest - Will Fry Find Enough Food?

[daizeUK]

Hi folks, I only got my first tropical fish 4 days ago and already one of them has dropped fry. 
 
The tank contains 5 adult platies and has plenty of cover for fry to hide so I was planning to leave them alone and let the fittest survive (not sure if any are actually still alive lol, but another female looks very pregnant so there will be more on the way soon)
 
Despite the available hiding places the fry seemed more interesting in breaking cover to look around the tank for food, then they would get chased by the adults.
 
I tried to crumble up a flake very finely and scatter it around some java moss for the fry to feed, but it just seemed to attract the attention of the adults and they started nosing around the moss looking for crumbs.  I don't want to draw attention to the fry's hiding places but I'm concerned they won't find enough food if I don't. 
 
What should I do?
 
 

 

[basboi85]

If you want to keep fry the I suggest buying a fry trap or making one yourself like i did until they are big enough not to be eaten by the adults but If you want to leave them be you will be surprised by how much food they would actually find.

And as you said survival of the fittest

 

[Lilfishy]

Livebearer fry are very good at avoiding being eaten by the adults.
For the first week or so they can survive on the insuforia in an established tank.
If you want to give them a better chance of survival you can get a pestle & mortar & grind flake or pellet food very finely for them.
Bearing in mind they will drop 30+ fry every 4-6 weeks, saving too many will mean you will soon be over stocked

 

[daizeUK]

This is a newly setup tank so I'm guessing that means the fry can't survive without some supplementation.  I won't have any of the algae/insuforia they would find in an established tank.
 
Any tips on how to provide crushed flakes without attracting the interest of the adults?

 

[daizeUK]

I came up with a plan.  What I'm doing is feeding the fish twice a day, morning and a few flakes in the afternoon.  At the same time I powder up a single fish flake with mortar & pestle and put it into a syringe, then draw tank water into the syringe and wait for the crushed flake to become waterlogged so it sinks.  Then I inject the powdered food into a couple of safe places where I know the fry like to hang out and at the same time give the adults a few flakes to distract them.  I'm also keeping a close eye on my ammonia levels to make sure the extra food doesn't foul up the tank.
 
The remaining fry are keeping their heads down much better today, I think they're learning that they get chased if they don't hide!
 
How long will it take before they are big enough to not look like a snack to the adults?

 

[PrairieSunflower]

My 2nd batch of platies I decided to not rescue any from the tank and 1 survived and I ended up moving it to another tank because I decided it deserved to live since it had tried so hard.

My next batch I rescued some and couldn't manage to even catch the others and 3 of them are still in there (now big enough to not get eaten). I feed that tank as an adult tank, however, and those babies aren't growing at the same rate as the rescued babies.

 

[daizeUK]

Hi PrairieSunflower, did you rescue them into a nursery tank or a breeding trap?  What is the size difference between your rescued babies and the fugitives?  How long did it take before the ones in the adult tank grew large enough to stop hiding?
 
Truth be told, I can't really afford to give many fry a permanent home though I would like to keep some of them.  My local MA is very good though, they have a special tank reserved just for 'lucky dip' platy fry and I checked and they will gladly take any I can't keep

 

[PrairieSunflower]

I have a small 3 gallon tank with a cycled filter that I often keep fry in for thereabouts the first month... that is generally when they are big enough to not be eaten (I keep neons, guppies and platies). They don't hide anymore around 3-4 weeks, I'd say.

I also use this tank as a quarentine tank so I do have a breeder net for back-up just in case. When I do not need that tank I move the filter into one of my other tanks to run so it remains cycled. It is a really small filter so it doesn't disturb the larger tank when I move it back to the small one.

Oh forgot to answer the size difference. The ones in the nursery tank are super friendly... so I measured them with a tape measure at about 12mm since they came up to the glass. The ones that are currently in my community tank are not as brave, I'd say they are probably 10mm or slightly less. That said. I also have 1 in the nursery tank that is maybe 5-6mm... not sure why that one is so tiny!

 

[daizeUK]

3-4 weeks, crikey that sounds like a long time to run the gauntlet of avoiding becoming another fish's dinner!
 
My QT tank is currently being cycled, otherwise I would be tempted to move the fry into it.

 

[PrairieSunflower]

Depends on the fish you keep as well. I have 8 fish big enough to eat babies (my neons don't even try but they will follow babies and stare at them in groups, very cute)... only 3 possibly a 4th do try and often succeed. The others don't care.

 

[daizeUK]

My ammonia is off zero and close to 0.25ppm for the first time this morning, so I think I need to back off on the powdered fish flakes, they seem to be doing more harm than good.

 

[PrairieSunflower]

Having babies means a lot of water changes. I aim for water changes every 2 days when there are babies. In order to grow properly, babies need to be feed 3-5 times per day.

 

[daizeUK]

Okay will do.  I wasn't sure if the fry were even finding or eating the powdered flakes but I guess they need them even if I don't see it.

 

[TwoTankAmin]

I would do as little as possible to help the fry survive. As was pointed out above there is something I like to call live bearer math. If you are able/want to save most of every spawn you will be needing to buy a new tank every few weeks for grow out. The females will drop fry every month and the older the fm gets, the bigger the spawns get. They also can have multiple spawns from a single contact with a male.
 
If you have live plants in a tank, especially java moss, you have infusoria. I used to use java moss covered rocks to feed cory fry. I would just move one from an established tank into the hatching tank once they were free swimming.
 
You do not need a mortar and pestle- just grinding the flake with your fingers works fine. And I have never found it necessary to feed live bearer fry more than once a day.
 
The biggest danger to the fry is not the adults in the long run. Its is the survivors from previous bactches who are not grown yest and can still get into the same hiding spots the new fry go. By about the the 3rd spawn the "teenagers" are eating the newest babies pretty fast.
 
I also do not believe in using fry traps (net breeders) for fish about to give birth. I believe it is very stressful and creates more problems than it helps. If you can get a small hatching tanks with lots of plants and move the mom there. After she gives birth put her back into the main tank.

 

[daizeUK]

Thanks for the advice, makes sense. 
 
I got rather excited the first day I saw fry in tank and started fretting because I wanted them to survive.  I've calmed down a bit now because you're right, I don't have room to keep all of them (although I'm confident I can rehome them easily), I was planning to add guppies at some point and I simply won't have space if I start getting overrun with platy fry.
 
Ideally I'd like to keep a single female from this batch as a permanent resident because I think it would be lovely to eventually have a tank stocked with home-grown fish.  That's something I can work on slowly.