Moving Pregnant Female Platies

With the proviso that you realise the 12 litre is too small for 2 platies plus fry in the long term: do a fishless cycle on the 12 litre, the reason being that 2 platies plus fry is very overstocked and you'll end up having to do several water changes a day with a fish-in cycle. Yes I know the females will be pestered a bit longer, and yes a lot of fry will be born in the tank but a lot will also be eaten. If you take a few rocks from the bottom of the biorb and somehow squeeze them into the 12 litre's filter (even one would help) that will kick start the cycle so it shouldn't take as long as a fishless cycle from scratch.


For anyone reading this who thinks I don't usually advise substrate to kick start a cycle, the rocks on the bottom of a biorb are the biological filter media 

Don't forget the female platies will carry on having fry every month for around six months once you have separated them as they can store sperm...........

And the boys might finally get over themselves and stop the macho stuff 

Possibly not  . Even with no females in there the males are likely to continue squabbling amongst themselves, although they don't tend to be particularly vicious to each other - just a bit of 'pushing and shoving' really. Just ensure you have some areas of the tank to which they can move away (e.g. hidey-holes, dense plants) and they should be fine.

Assuming platy males develop like endlers, watch the anal fin. With endlers the first ray elongates before the rest of the fin shrinks. As soon as you see that take those fry out before they become fully functioning males.

The site I use is aquarist classifieds. I usually advertise surplus fish as free to anyone who will come and get them.

Thanks both, will give it a try when they are a bit bigger.