ok i have a 90 gallon tank with a 3"oscar, 4"-5"clown loach and a 4"-5" pleco these
and i was wondering if i could have any frontosas in itif not could i have any in a 40 gallon
I would side on the side of not trying it. In a 90 the O might be ok with the front if you put him in early and have them growing up together, but the O will grow up much much faster. And a 40 isn't good for a front at all.
fry in a forty yes. I would also recommend getting something that will be 6ft and more than 18 deep. This way they can turn around and swimming when old.