Sense I don't know how old your two fish are it's hard to say what they are doing. But yes they can breed....they are both from the Cichlid family, but don't get your hopes up to high.

If the Jack is dominate in your tank he could just be showing that.

Most times when a Cichlid wants to mate they will do like a little dance, shaking their body side to side, and sometimes make odd movement with their mouth. If your Oscars is doing this I say yes she wants babies. The Jack has to be of a larger enough size to mate though. Never heard it called heat before.

So like I said, not knowing the age/size of your two fish it's hard to say if they are going to mate or not. If for some reason they do...watch them, they will eat the babies. If you want to keep the babies...seperate or put a lot of small rocks piled up for the babies to hide in. Thats the only way my Cichlid babies have ever made it. My tank is piled from bottom to top with slate rock....and I had enough babies to last a life time. The pet store love me. LOL

Hope I help you out some. Boy if a Jack and a Oscar do have babies...I want to see a picture of them, I would love to see how they look.