Will a spawning cube be effective

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Aquarium Advice Activist
Mar 17, 2022
So I was thinking of making a spawning cube inside my 15 gal community tank cause I'm starting to run out of space. The 15 gal is gonna be for some lampeyes, pygmy cory and male guppies. I'm gonna be putting the male and female guppy inside the cube for when I want them to spawn and I'm gonna be leaving the female there till she drops the fry's. Question is will she actually drop her fry there and will she eat them?
Your female guppy will already be gravid (pregnant) due to mating with the male in the tank and possibly other males she was with before you got her. Male guppies impregnate the females with sperm packets. The female can carry 6 or more sperm packets from various matings with different males and use one packet per batch of eggs. The females can carry these sperm packets around for months and use them to fertilise a batch of eggs when conditions are good. The eggs develop and hatch inside the female and the fry spend several more weeks inside the female developing further. After about 4 weeks, the female gives birth to a batch of young and it can vary between 10-100 fry, sometimes more, sometimes less. Young females have smaller batches about once a month. Older females have bigger batches about every 6-8 weeks.


If you want to breed guppies, put the female in a well planted tank without any males. Feed her well and when she is ready, she will give birth. The babies will hide among the plants and if the female is well fed, she won't normally eat the babies. Most females don't eat their young unless they are stressed or really hungry.

The best plant for baby livebearers (guppies, platies, swordtails, mollies) is Water Sprite (Ceratopteris thalictroides/ cornuta). It is a floating plant that has lots of branches and nice fine roots for the fry to hide in. You can also plant the Water Sprite in the gravel if you get too much and it grows into a lovely light green shrub.
Im getting juvy pairs and they're usually separated. I'm getting different pairs so I'm putting the males and females in different community tanks. 1 tank for only females and I'm only going to put them in the spawning cube with the male when the timing is right. So basically I'm hoping to raise the fry in the cube and when they're big enough, gender them and release them in the bigger tanks.
Question, how long can fry last without aeration? I've been watching a couple of breeding videos and saw people using breeding cages with holes at the bottom inside tubs so fry can easily drop down to the tub away from the mom.
Aeration helps improve the gas exchange so you get more oxygen (O2) into the water and more carbon dioxide (CO2) out of the water. If you have a large water body with a big surface area (length x width), you get good gas exchange. A small surface area will have a poor gas exchange.

Depending on the number of fish in the water and how big they are, will determine on how much surface turbulence you need for the gas exchange. A couple of baby guppies in a 20 litre (5 gallon) tank probably won't need any aeration but 100 baby guppies will.


Don't use breeding cages/ traps. They stress the female and make her more likely to have problems giving birth or eating the babies.

If you want to get the highest number of babies surviving, have the female in a decent sized container (40 litres plus) with lots of plants and feed her well. She will be relaxed and comfortable and less likely to eat the babies. Most guppies don't eat their young any way but having lots of plants and feeding the mother well reduces the risk even more.

And don't move heavily gravid (pregnant) fish because you can stress them or harm the adult and or babies. If you have the females in a tank with males, move the males out and leave the females where they are.
Nice thanks. I found a 15 gallon tub where I can put the fry while I wait for them to grow big enough to join the community tank. Problem is it's black so it's gonna be hard to spot the fry.
Why didn't I think of that -__-
Or maybe I could use a white plastic sheet or tarp. I see some backyard breeders making mini ponds with tarp.
You don't want sheets of anything on the bottom of tanks or containers because gunk and baby fish get stuck under them. Just use play sand or gravel
You could always paint the inside of the tub. There's a paint called Krylon Fusion that is safe for inside the tank or pond once cured. ( There are a number of Krylon paints but only the Krylon FUSION is safe for inside the fish containers. )
I got some people offering to sell me one that looks pretty well made that it looks like the tarp was shaped for the inside and no area for anything to get stuck on. But I think I'm going to try to find some transparent ones instead.
Thanks! That's really useful cause I've been trying to figure out if there's any aquarium safe paint
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