Yeah in my 4ft community, the male killed my female, I thought they had been paired by the breede but obviously not... is 40 gallons ok, was looking about and want to keep it relatively small, the tank is just about 3 and a half foot
Yes, that should be fine. Something else you probably already know, but if you intend raising fry, do not include catfish as they are nocturnal. My cories and whiptails got the eggs three times and shoaling fry once, during darkness. I wasn't intending raising them, just letting nature be itself, so it didn't matter, but the parents cannot defend during darkness.
Even daylight can be tricky; several years ago I had a pair of common rams in my 90g, and one day I was enjoying watching the female shepherding the fry (about four days old) around, and all of a sudden two cories just happened to come round a chunk of wood and into the shoal. Well, it was only a matter of seconds before every single fry was gone. The female tried to defend them, but of couse corys are not bothered by to pokes and nibbles when in a feeding frenzy.