How do you separate your male fry?

[1stAquarium]

I would like to breed my bettas and have done a lot of research on it but first I need to figure out a way to separate all my male fry for when they get older and become aggressive towards each other. I know about the jar method but has anyone figured out a less space consuming way? Also some way to heat this area?
I was thinking maybe a large plastic box container with aerated lid, with a reptile 'air' heater or something to keep it warm enough (I live in the UK and it's currently snowing!) and jars or whatever storage containers I decide to use (maybe something that tesselates better than jars) inside?
Am I forgetting/missing anything? Obviously I would do water changes in place of filtration.

[DragonFish]

Honestly, I don't think there is a way to separate fry out that isn't space consuming...unless you have a very small spawn. Even barracks take up quite a bit of room, though are probably the most organized way of going about it....

A large plastic storage bin with a heater, as you mentioned, where you can float the cups would work just fine, though I'm not sure how that would be more space-efficient....you'd need one big enough to be able to hold all of your jars, so it'd take up just the same amount of space as just setting the jars next to one another I'd imagine....
Though the bin with a heater is definitely a good idea if you can't keep your room temp warm and stable. ;)

No matter what though, you'll need a LOT of space if you plan on a spawn larger then 20 or 30....I think thats just one of the downsides of breeding

[1stAquarium]

Yeah, I have a cellar with lots of space so I'm sure I can create somewhere safe down there away from the cats!!
My room temp varies a lot as we have the heating on when we're here, but it's off most of the day and as I say it's pretty damn cold here right now! So do you think a storage bin full of jars with a heater for the air inside would be sufficient? I have no idea about the heaters you can buy for reptiles like this, having never kept them.
What do you mean by barracks? Stacking containers?

Or maybe a reptile heat mat?

[doggyhog]

You can do what's called a "Water Bath" which is filling the bin a few inches full of water then sticking the cups/jars in. This keeps the fish in the cups happy and warm, while you can let some of the females and less aggressive of the spawn free swimming around the other cups.

Just get an Aquarium heater and it will work. If you want even less water changes, drill holes in the cups so that water can flow through easily.

[1stAquarium]

Genius!! I'll do that, thanks very much! So now I just need to buy the biggest plastic box I can find, some see through plastic cups and a 25 watt heater or 50 watt do you think? Assuming I end up with the maximum amount of cups!
What about a filter for this box, is one required?

[doggyhog]

I'd go with 50 watt.

A filter not NEEDED but highly recommended. Get a corner filter or Sponge filter.

[1stAquarium]

Ok thank you, I'll just put enough water in to cover the filter then. I also have a 17 US gallon tank which I will be breeding the bettas in, so a lot of the females will be able to live in there.
I am looking at how to make my own brine shrimp hatchery for when the fry are born, any tips on how to make one in the simplest way?