I for sure encourage players to read room descriptions, including the semi-random bits. Read command outputs. Read all the things. Take note of how the game world is described as that is your characters perception of the world, if not their opinion.
I know it's hard to do after playing for years upon years upon years. A lot of us start to just not see most of the details, our eyes only taking in the key bits like room names and exits and objects/characters present. But try and slow down and read it all now and then.
Further, don't only consider what the game presents you as what your character senses and hears. Also consider what the game never once mentions your character seeing or hearing. It's sometimes surprising to suddenly realize that there are whole sector wide constructs that a vocal minority of the population (AKA some players) push that has ZERO existence in the game. That are just the claims of a few PCs witch no PC ever perceives.
So, while I don't mind the fish being a matter of IC debate (though I hope it dies eventually as some things have a tendency to live forever), I do understand the source of the frustration. We as players really should do our best to be careful with how much liberty we take over reality. Sometimes it ends up, in my opinion, being an unintentional form of power posing on a wold scale.
I also admit to inventing nonsense up IC all the time about particular things that don't have any real affect on anyone or anything. It fills the world out for me to have superstitious or erroneous beliefs that are character quirks. I remember my first character wondering about the fish and not knowing, which I took as an IC motivation for something that actually went into the whole character's arc. Those fish, for me, have rp history. Its silly, but its part of the character's story in a memorable way.
I know some people are purists but I love that this game doesn't force everything to be completely literal. We have room to breathe with clothing, artwork, tv shows, even actual IC science. I have been frustrated by other games that force me to be literal all the time. It's difficult to explain, but my RP partners would likely know what I mean (maybe better than I do) - especially lately . If everything has to be as it appears, all metaphor gets tossed out which is a super tragedy and ends up feeling oppressive. (I have played games like this) I know there are people who don't engage as easily with metaphor than others, but I also don't engage with some things so great either. Preferences and differences are great.
I get that you can't go nuts on everything and I do consider myself pretty grounded, but at the same time I do enjoy that not everything is absolutely pinned down. A lot.
Sometimes staff decides things do need more definition and that's fine, great even. But when there's room for the world and people to be flawed, I think thats helpful for storytelling. If they suddenly decide to make it crystal clear about the fish, I'll be a little bummed but I'd understand. Just figured I'd toss in my two chy :)