I'm thinking about putting a betta in my dirted (and empty) thirty-ish gallon, but there are a few spots where the dirt is exposed. I want to add a bit more gravel to cover these spots but I found a dead roach on my bag of gravel, but not inside it. It's an open bag which is why I'm concerned. Is it safe to use the gravel or should I assume that roaches have touched the gravel and toss it? (I'm absolutely horrified by these nasty creatures.)