First of all "The Shape of Water" is beautiful and magical, a fairytale that is easy to enjoy and fall in love with. That much does not need you to look any further - an enchanting lovestory if ever I saw one, plain as day.
On second glance however it's small, humble scenery, this intimate dream we are invited to share, aims at something much, much more important. Something that may not even be about romance.
We all have, or at least had, ideals. Until we give up, or realize them. Thereby lofty ideals become firmly rooted in reality. Alas! more often than not high ideals become nothing but a facade in the process, a rallying banner used to pretend we'd still know what is what, how to be good, how to do the right thing, or why we became who we are to begin with.
For some the banner is "christianity", others advocate "tolerance" or one of a million other names we've given. What does that even mean? Perhaps we shouldn't swear? Perhaps it requires great strength? Perhaps there's the book telling right from wrong? Almost everybody genuinely tries to do the right thing, and so do this film's characters. Down to the overdrawn bad guy, each in his own fashion.
If you are open to it I am sure you'll feel what it is, what allows this wonderful film's protagonist to humbly walk that path. A path that all others use so much more power, knowledge and discipline to find and follow, yet fail.