They all look quite similar actually. According to my latest online finding, silverfish and firebrat are grouped under Zygentoma (formerly Thysanura), leaving bristletail in Microcoryphia. However, I have found conflicting information from other sites which consider silverfish and firebrat to be synonymous with bristletail. To all the professional entomologists out there, I would like to know your perspective on this.
Silverfish?