maximum number of BN's in a 4 foot tank ?

lengh 39-40 inch, depth 11-12 inch, height about 15 inch

how many adult BN's would u suggest maximum ? i am looking to breed em at the min i have 5 adult BN's (breeding) and 4 babies that were born in november i think. (from curby)

i am not keeping any other fish in there. wot's the maximum for a tank this size ? and am i over the maximum ?

4 females and 1 male would be fine. make sure your fillter is upto the job though.
Also make sure you do regular water changes. your also going to need a growout tank or two

Out of 9 fish total ( 4 being juvies) what sex ratio's do you have? over the next 12 months you could probably establish
2 breeding groups (so maybe another 3ft tank is in order)
9 fish in you 3.5ftr should be OK for a while but since your tank is low profile( 15inch) you have a smaller water capacity
compared to a tank that's 20inch tall(obviously), so with 9 B/N in there you're going to be doing a fair bit of maintenance
and like deano said "I hope your filter is up to the job"
J