Thank you for adding your fish to your profile, I sure wish more members would get in the habit of doing this, it makes a swift diagnosis easier in the event of any problems.
The reason rdd asked is that some fish are more hardy than others, and better at surviving a traditional cycle. Different fish produce more or less waste as well, there is a big difference between say 18 ottos, 18 zebra danios, and 18 plecs.
Just by looking breifly at what you have, your tank is too small for the clown loachs & black knife, and may be depending on the species of gourami. Withot those it would be considered overstocked for a mature tank, way over for a traditional cycle. The neons are way to sensitive to be cycling with, as is the goby.