What a difference a couple of days make

So after 5 years without a fix, I finally get back into the fish game. Picked up a trio of Inkfin Calvus and a pair of gold occies from FryBabies whom I'm lucky to live near on Friday.

Looks like the Calvus displayed text book settling in behavior. Looked VERY uncomfortable for the first day or so and are now confidently swimming around and feeding. If I hadn't read some of the threads highlighting this I'd have been worried.

One question though. How long should it take a pair of occies to, well, pair? There wasn't any certainty that I picked up a pair but with the offer of an exchange I was perfectly happy to give it a go. The larger one has been aggressive toward the smaller one when it is close and the pair have also done a lot of fast 'twitching' when they are near each other. The smaller one has currently taken up residency in a single shell at the other end of the tank to the main shell bed by the Calvus's rocks. When I moved the shell to the main shell area the larger one got aggressive so I moved it back where it seemed happier before. Even though I put a large rock in the middle of the shell area to break line of site the larger one would still not leave it alone.

Do you think I have two males or is this behavior typical of a M&F?

Thanks