I agree very rushed maybe there's side stories? Let me see the demon spawn at least! The fish alone in the big tank is symbolizing how yooil is held captive alone and away from everyone else isolated constantly watched with no privacy his life is under control of hwan.they did similar symbolism in Pearl boy with the fish tank in pilwons home.
the fish is actually Betta fish, pretty much symbolizes the Beta MC and his way of controlling his environment-- hence, "Raising Beta"
Fish is shown here as how everything is on palm of Alpha he can get anything under his hand, controlling he never fails to achieve anything he wants and as "beta catched by his trap he put in sea(world )he found his frvt fish that he never want to let go"--that's what it symbolises.
rushed ass story? why the hell was they fish everywhere??? and all the random ass shit bro