Pacu & bala sharks are NOT good tankmates for a BGK. BGK are pretty nice fish, they only eat fish that are small enough to fit in their mouth and that is usually when they are much larger. They are a small growing fish, but in adulthood would need a very large tank, I am talking 90g plus, as they can reach 20"! They also are scaleless and extremely sensitive to varying water parameters and are easily killed by ammonia and nitrite spikes, and they can not handle things like copper and other meds and metals in water.
Bala sharks get HUGE!!! A 100+ gallon tank is needed for just one. Pacu, my dad had one for years in his 110 gallon tank, they are mean and will happily throw any tankmate out of the tank if it feels the need to do so...found our large oscar crispy on the hallway floor after the Pacu tossed him out of the tank.
A BGK can get along with a gourami, if its the right species. And with gourami, some can be really nasty to any tankmate.
A tank only set up on Friday has yet to cycle. Cycling can take a varied amount of time, normally around a few weeks. And for a tank set up just Friday to have this many fish in it so soon, it wont be pretty. The raising ammonia for the bio load in this un-cycled tank is going to spike high and kill most if not all the fish in the tank in any given amount of time.
My advice is to re-consider your stock, the only fish that I see acceptable for your tank size is the gourami, but surely not that many of them, the rest should be returned. After returning them, you need to cycle your tank. http://www.tropicalfishkeeping.com/f...m-cycle-38617/ http://www.tropicalfishkeeping.com/f...tocking-38626/ http://www.tropicalfishkeeping.com/f...quarium-74891/
These topics here on TFK should help explain to you the details needed to understand the aquarium for water quality, cycling, and stocking. For any fish species you have or plan to have, you can find information on them in the Tropical Fish Profiles tab at the top left of any TFK page.