I could fill this post with an enormous amount of rules that mostly work for any novel you want to write, but that isn’t the point here.
Any writer, especially the ones who are just beginning, ask themselves now and then: Should I do this? Is that allowed? Can I write this scene like this? This is amazingly good and will help you a lot in order to build your story and give your work some quality, but let’s talk about writing rules in general: they are guidelines, not rules!
You can, if it works
No matter how peculiar your ideas might seem, if they work for your story, then you can use them. This is the only actual rule.
Do you want to tell your story from the flea point of view? You can, as long as it makes sense in the context. Now, you are probably thinking: OK, so how can I know if it works? The answer is easy: try it. Experiment, write different versions of a scene, for example, to determine who should be telling the story, if the narrator is sarcastic, funny or serious, if the narrator gives its opinions or merely describes what is taking place. You decide.
One of the major problems a writer faces is how to tell background story and flashbacks are a commonly known way of doing it, however, most people would say “no” to it. So, are they allowed?
The reason flashbacks seem to be so hated is because you’ll need to stop telling the main story, to introduce the ancient story and most of the time, it’s not worth it. Again, these are guidelines, which work most of the time, but your story might very well be the exception and that is OK!
If it is, in your particular case, so important to describe something that happened before, do it! And that goes for any other guidelines too. If your story works best by breaking a rule, then please do it!
Experiment! Have fun! Try new things! Maybe you’re a visionary making something new and amazing, or maybe you’ll fail and need to start all over again. It doesn’t matter. There are so many options out there to be explored! Just enjoy yourself and never stop writing!