which has the "V" and which has the "U" on the venting?If you introduce 2 males you're going to get aggression. Best bet is to get your oscars at 5" or better and vent them to get a male and female. Another option, if smaller oscars are all that are available, is to purchase several and raise them together. Once two of them pair up, keep those and remove the rest.
the paragraph is confusing....it appears they are saying the male has a tube? Does the male actually have a projecting sex organ at times that comes out of his body?