stubby fins

I have some blue babies I'm growing on, most are developing fine, but 20/30 of the smaller ones (5p sized), that have been in a rather crowded tank (I have thinned them out again at the weekend) have what I can only describe as stubby fins, (the blues have much wider fins than the other fry I've raised), these remind me of the rubber on the top of a pencil, they are proper fins, just a bit on the short side.

Now they have more space to grow, will their fins improve in proportion?? I'm water changing daily and feeding twice a day, is there anything I can do to help or is it just down to more space?

Could I for instance spread the stubby ones and put the better proportioned ones back in a slightly more crowded environment?? Not ideal I know, but I don't have a fish house, I'm just doing my best with the 5 fry tanks I have in my front room/Kitchen.

As long as the damage isn't too extensive, now they've got a bit more space it will probably heal fairly quickly.

Lack of space is always a challenge no matter how many tanks you have.
Often the fastest growing fish turn out to be males, if a tank is becoming crowded I try to catch out the largest fish as "keepers", a few weeks later the "keepers" will have grown, but there will also be a number in the original tank that have had a growing spurt, often, most of these will be the best females. Now they're a bit larger I tend to sort through the "keepers" selecting about half of them (the rest go to the shop) and I then select the best of the rest to become "keepers". the others are the "also rans". Sometimes fish get demoted to the "also rans", or one of the "also rans" turns out to be a late bloomer, and wins promotion to the "keepers", but in general I periodically pick out the largest "also rans" and take them to the shop, often along with a few rejects from the "keepers" tank.
This way, I can provide the shop with a steady stream of reasonable sized fish, whilst maintaining grow on tanks which aren't excessively over stocked. I realise that owning the shop makes this process somewhat easier, but most shops will be grateful for a regular supply of consistently sized fish.
Finally once I'm left with just "keepers" I tend to select about half a dozen to grow to adulthood, and the remainder come to the shop and get sold as "medium angels" or "select grade" if I feel they're deserving of the title.

OK thanks Rob fingers crossed, interesting about the male/female bit though