I think that's going to have to be the plan. Keep the favourite ones, fry in their own tank (I've got a very large glass jar in the play room with water in it from the aquarium so we can occasionally catch a couple of fry to look at and draw. It's probably terrifying for the fry but i think its important for kids to be interested in animals and they swim about in there for a few hours til they forget the trauma and go back home). I don't mind a semi regular trip to a pet shop with the over stock. They can go from the fry tank to the shop when they're too big for it.
Tomorrow we're taking 2 of the adult platies to the vet (yes really, at £7 per pet no less) because they somehow got in the tiny gap behind the filter and got hurt. And because I'd said vets are for when our pets get injured, that's where we're going. One is fine. Just a bit of a grazed nose, the other...Well, i think tonight will be iron man's last night if I'm honest. So i have a sad 4yr old but it's a thing they have to learn..I'm just glad it wasn't Skye! Of course I'm also glad iron man doesn't seem to be suffering, he/she is just sitting sideways breathing normally. I just hope the vet has a kid friendly way to put a fish to sleep or i might lose faith in them.
But yes. Thanks for the advice.