Red Fin Tetras Won't Stop Breeding!

So a few months (6ish) back I brought 10 columbian red fin tetras to  encourage the 9 very shy cardinals I  had. Worked a treat and the cardinals aren't as shy and come out all the time now. Only problem is the red fins can be a little nippy with each other so I figure give it 5or 6 years and we can replace them with something more peaceful.  Fast forward to last month and a 5mm fry is spotted, then every week we have seen a new 3-5mm fry! The original is nearly as big as the cardinals. Ive caught the bigger ones in the act of spawning this week. Can i do anything to stop them?! I have a home for 7 of the large adult red fins, do you think my lfs will take the rest. They are starting to breed like guppies!

Sometimes nature blows rasperries at your plans.   
I don't have any experience with these fish, so don't know if there is anything you can do to make them stop, but it is worth phoning your LFS and asking them if they will take your extra stock.

Temperature might be a key thing, I've found if I up the temp in my shrimpery a little the pygmy cories will stop spawning.

There is a specific red fin tetra forum here http://www.fishlore.com/fishforum/bloodfin-tetra/ they might be able to help you further

Hadn't thought of that,  id been experimenting with lowering the temp to 23c after having it around 25ish. I'll pop it back up and see if that calms them down.  Thanks for the link too

They're quite a hardy, easy to keep fish which are ideal for beginners (I've been swatting up  ) It may just be that they're so easy to keep they spawn like mad but I guess you'll find out shortly