Ok this is strange and i am not sure if they can even breed BUT my what i think is a female oscar that i have owned for 3 years has JUST started doing this...she has been shaking her butt or whatever you want to call it like the usual mating thing and she has been moving rocks into a corner of the tank! now i know this is typical oscar behaviour but she has NEVER EVER done this before in all of her 3 years she has never been a rock mover. Now this is the strange part, in our tank we HAD a convict but it died last week because the oscar and the dempsey we have in there were picking on it so she was basically bullied to death but now i am wondering if it had something to do with a mating thing only because of this new behaviour from the oscar but what i don't know is if it is common for a dempsey and an oscar to breed? the way the oscar is acting it is like she wants to become a mama and the dempsey is a male who all of a sudden has become so bright and colorful (more than usual) so am i just being odd in thinking this and its entirely impossible or could this be a sign of babies to come?? Also she has been guarding the area she has dug up and rock piled and won't leave it...i just don't know if the 2 can even breed...people have told me i am looking into it too much as this is typical oscar behaviour but it is not for her i mean in 3 years she has NEVER done this!

An Oscar and a convict cannot breed because they are different species of fish, although they are both cichlids

Oscars will often move rocks around in much the same way as fish that breed, but it doesn't necessarily mean they will ever lay eggs. However, a female Oscar can lay eggs on their own, but they obviously won't hatch without the male present.

Can a dempsey breed with an oscar? i can't seem to find confirmation on that one....if not then i won't be expecting much:) funny thing is she left the area for a while and is constantly wiggling all over the tank and now the dempsey is at the bottom of the tank right in the area she has been emptying!

An Oscar will not breed naturally with a convict. Whereas dogs and cats can in theory can breed with each other whatever species they are, the same doesn't apply to fish because they are completely different species, although they are still in the Cichlid family. Can you imagine what you would get if it was possible to cross breed a neon tetra with an Arapaima?

Oscars and your Jack Will NOT breed! As far as I am aware Oscars only breed with Oscars!

If oscars and JD could breed then we would of seen the cross breeds in shops,I think its safe to say they cant breed. Your fishes behaviour is because of the convict dyeing. This has changed the balance of the tank and is causing unusual behaviour. Once the pecking order and territorys are sorted out everything will settle back down