Its not going to last trust me, the current tank size is also far too small to hold any of your fish- they may look small right now but they are only babys in comparison to what they'll be in a year or so time. Your irredescent shark will enventually be 3-4ft long, which is the length or longer of your average 30gal so it won't even have room to turn around.
Also there is little point of me advising you how to save your fish other than rehome them, the shark is not going to stop getting beat up and the others will rip the hell out of each other when it does die.
I could say "yes your fish will be ok, just give them some time to get to know each other and they'll be fine" but i'd be lying if i did. You came on this forum for honest advice and there isn't going to be a single member here with an ounce of knolege on fish keeping thats going to tell you that your fish are going to co exist with each other happily.