Best thing is to try... i found that after introducing rams to my tank the RTBS took an immediate disliking to them... I then had to seperate them into differing tanks (im lucky to have more than one tank i guess)
Try it and see, if there is going to be a problem its likely you will see it in the first day, there is also the problem that shark types get more aggressive with maturity and therefore nothing may happen for 6 months then suddenly you'll notice the shark become territorial, in a huge tank it may not be a problem but in a 50g or smaller its likely there could be clashes if the shark becomes territorial.
Sorry cant be more help than that im afraid, may be worth waiting for someone whose kept rainbow sharks to post here with any ideas.
Try it and see, if there is going to be a problem its likely you will see it in the first day, there is also the problem that shark types get more aggressive with maturity and therefore nothing may happen for 6 months then suddenly you'll notice the shark become territorial, in a huge tank it may not be a problem but in a 50g or smaller its likely there could be clashes if the shark becomes territorial.
Sorry cant be more help than that im afraid, may be worth waiting for someone whose kept rainbow sharks to post here with any ideas.