I am new to this, too, but I can see that you have several things to watch out for: You started up this tank with a lot of fish in it, and I would say that you have too many to survive there -- if it was a "cycled tank" (meaning all had settled down and gotten good bacteria to grow), then that would be fine. But now, if you can, you should move 1/2 of them out to another tank. Or begin treating for too much ammonia, as that is what the odor is all about. You can get Prime to treat it, and AmQuel for the ammonia and nitrites. Secondly, you will need some test strips to keep checking on the ammonia level, as that will kill fish, too, or make their immune systems very fragile. And there could be some disease in there too, you didn't mention if they had any problems with that. Your Creamsicle Lyretail may be a bully, but the fish are weak after being put together in this tank, and can expire quickly. You have only one Cory cat in there, and this one doesn't like being "alone" with no others to hang out with.
So first, treat the tank and get a filter if you don't already have one; secondly, try to remove some of the fish if possible; and thirdly, if you have too many males, they can stress out the females, too. This is a lot to remember, but being new at this, like me, there is a bunch to learn. Good Luck with all of this!