"Sailing to Byzantium" with Pet Fish

On Saturday my son was saying how he would like a pet fish. I had a few very temporary goldfish once, and a betta that bore with me for several months, but I am not worthy of pets. I was thinking I could suggest an alternative to my son: perhaps of something like the mechanical fish tank I saw at a dollar store once, which lead me to Yeats's "Sailing to Byzantium" and an insight: the desire for the mechanical bird in an artificial tree is perhaps not only a desire for the invented immutable (a good received reading of the poem), but also for beauty without responsibility and risk.