Please read:
Irridescent:
Iridescent Shark
Balas:
Bala Shark Profile
You really need to take the fish back please. they are to big for your tank NOW and they will outgrow your tank as well.
You also say that Today you bought all of these fish and the tank, which tells me that you have not cycled your tank. Please read the stickies on cycling your tank. Unfortunantly It is a misconception that you can just get a tank fill it with water and decorations. sorry but you can't. A tank needs to be prepared first before it can sustain life. Don't worry 99% of us all did this too the first time, then when our fish died we found this site and sites like it to answer our questions why.
I would also take the 10 gallon back if its possable, and get the largest tank that you can afford and house. You will be happier in the long run. And it will allow you to get a wider range of fish.
Another suggestion would be to go to a petco, petsmart, walmart, or any fish store and take a look at thier stock, then when you see a fish you like, come home FIRST and research it, (GOOGLE IS YOUR FRIEND) or ask us.
Read this stickie, its pretty good in my opinion and will get you off to the right start.
Setting up a new tank - MyFishTank.Net
good luck
and dont be afraid to ask questions and welcome to MFT!
Kevin