To start off with, the best you can do for yourself AND the fish, is take the fish back to the store and get some store credit for it...It is so very cruel and inhumain to be using a fish, even a damsel, for cycling a fish tank..If left in, and it survives the potential ammonia poisoning, it will cause you so many problems when you next come to add any other fish to the tank...
There are many ways to cycle a fish tank that. You can use pure ammonia, a dead shrimp or prawn, fish food...
View the cycling sticky written by myself and Yash in the marine newbie section..
Your choices are a little limited when come to your hood problem...Am afraid to say you only really have two choices. Either cut the hood, or change equipment..I cant see any other way that you can acheive your goal...
Sorry to be the bearer of bad news matey...
Niko