welcome to fishlore, im glad u found us.
to be completly honest, you really need to bring back every fish possible to the fish store, because you have some serious problems down the road if u dont.
dwarf puffers and crayfish should have a tank to themselves, because they are very aggressive. those would be the fish that DEFFINETLY need to go back
if you cant get rid of any, i would condition the water with a product that neutralizes ammonia like PRIME, and be doing AT LEAST 40% daily water changes.
if you can find bio spira, a product that instantly cycles tanks, i would purchase it and add it to both tanks
good luck! take back wat fish you can (hopefully all), keep up daily water changes, and READ READ READ!
