Akasha72
Warning - Mad Cory Woman
I saw a bronze cory recently that was humungus. I was gob-smacked and it takes a lot to leave me speechless lol. Mine had better not get that big or I'm going to have to find room for a 5ft tank 

10 inches?! Or 10 cms?10 inches really would be a mental size for a bronze cory, whereas 10 cms I could see happening...
ps I'll move this to the corydoras section
If you had no other Corys I'd think 12 Pandas in a 3 foot tank is fine, in fact you could probably add even more. Of course it all depends on what other fish you intend to keep with them & whether you have sand substrate, etc. Pandas are one of the smaller Corys. I wouldn't recommend 12 Emeralds or Peppereds..............
The main problem I have with large numbers of Corys is knowing whether or not all are getting enough food and generally keeping track of them.