When will the fry be a problem?

[Ckenny]

Hello everyone! I'm excited to join the forum and hope this isn't a question that is asked often (I looked and didn't see). I have a 20 gallon tank with 4 Cory catfish, 4 shrimp, a mystery snail, and two Mollies. Well... those and 20 something Molly fry. I didn't realize my fish was pregnant until about a week before she gave birth (I read it takes 60 days, so I was planning try to separate her out before hand.... but too late) Anyways, I have heard that the fish fry can crash the tank. I've been doing daily water changes at about 20%. I am hoping to get a bunch of the fry out and put in a small 5 gallon tank that I used to use and eventually into another 20 gallon tank. How worried should I be about these fry crashing my tank. They are about a week old or so. I thought the Mollies would eat them... but they seem to get along. Anyways, thank you for your insights.

 

[GaryE]

It's really as they grow that you would have problems. That gives you lots of time to catch and move them.

 

[Sgooosh]

Hello everyone! I'm excited to join the forum and hope this isn't a question that is asked often (I looked and didn't see). I have a 20 gallon tank with 4 Cory catfish, 4 shrimp, a mystery snail, and two Mollies. Well... those and 20 something Molly fry. I didn't realize my fish was pregnant until about a week before she gave birth (I read it takes 60 days, so I was planning try to separate her out before hand.... but too late) Anyways, I have heard that the fish fry can crash the tank. I've been doing daily water changes at about 20%. I am hoping to get a bunch of the fry out and put in a small 5 gallon tank that I used to use and eventually into another 20 gallon tank. How worried should I be about these fry crashing my tank. They are about a week old or so. I thought the Mollies would eat them... but they seem to get along. Anyways, thank you for your insights.

if the mollies are peaceful to the shrimp, they will be used to smaller animals and not eat the fry

It's really as they grow that you would have problems. That gives you lots of time to catch and move them.

yes, when they grow up, the bioload also increases

 

[Ichthys]

They take about 30 days, not 60. And she’ll probably have more batches.

 

[sharkweek178]

if the mollies are peaceful to the shrimp, they will be used to smaller animals and not eat the fry

yes, when they grow up, the bioload also increases

If you want them to eat fry, then skip a few feedings.

 

[GaryE]

A lot depends on your set up. Hordes of fry are coming, for sure. When I was keeping about 7 different molly species (in individual species tanks), I could go away for a week leaving the fish unfed, and fry would be left alone. That is, unless the tank was too small for mollies (under 30 inch front glass, in my world view). Then there would be some cannibalism.

So there may be some reduction in population coming.

 

[Ckenny]

They take about 30 days, not 60. And she’ll probably have more batches.

Oh boy... My daughter loves it, but I could see this becoming an issue...

 

[Ckenny]

yes, when they grow up, the bioload also increases

So how big before they are dangerous? I know that isn't an exact science, I just want to be cautious.

 

[Ichthys]

Keep an eye on your ammonia, nitrite and nitrate. If the bioload gets too big for the filter you’ll see (one of) the first two, and the nitrates will get higher. Livebearers won’t overpopulate a tank but the bioload might get bigger than you want, needing too many water changes… or a filter upgrade.

 

[biofish]

Once the fry get big enough you can sell or donate them to your LFS! Cause yeah…. It’s just gonna get worse from there the more you keep. The more fish means more available to give birth and then suddenly your drowning in fry LOL. The best way to get them to survive is to give them their own tank, since the fry are so small that any fish can eat them if the desire hits them

If you don’t wanna get swamped by too many fry, I’d suggest having an all male mollie tank or getting a slightly bigger centerpiece fish that’ll keep the numbers down

 

[Ckenny]

Once the fry get big enough you can sell or donate them to your LFS! Cause yeah…. It’s just gonna get worse from there the more you keep. The more fish means more available to give birth and then suddenly your drowning in fry LOL. The best way to get them to survive is to give them their own tank, since the fry are so small that any fish can eat them if the desire hits them

If you don’t wanna get swamped by too many fry, I’d suggest having an all male mollie tank or getting a slightly bigger centerpiece fish that’ll keep the numbers down

I'll talk to my shop and figure that out. A bigger centerpiece fish, for a 20 gallon (2 mollies, 4 pigmy corys (although I want 3 more), 1 mystery snail, and 4 shrimp (although I'd like a few more too) any recommendations? My daughter (6) is becoming obsessed with Betta fish. Would a Betta be good in a tank like mine? The flow from my two filters isn't high, I have a fair amount of plants, but I have never kept a Betta. Or is their a better choice?

 

[Slaphppy7]

Welcome to TFF

For the most part, bettas should be kept alone, in a tank of their own. Rarely do they work out well in a community tank.

 

[Ckenny]

Welcome to TFF

For the most part, bettas should be kept alone, in a tank of their own. Rarely do they work out well in a community tank.

Shucks, my daughter saw all these youtube videos with them in community tanks. But they are probably more experienced than me.

 

[Slaphppy7]

Sometimes it works, but not often...just depends on the temperament of the betta, which there's no way to predict

Is the tank a 20G tall or 20G long?

 

[Ckenny]

20 tall, I just got a 20 long but need to get it set up before I can add any fish.