I am usually busy and distracted, and my life is complex enough that I don't keep to a regular schedule. I don't mean to, but I forget about them. Basically my plants and fish live in a Darwinian environment where only the strongest survive.
That said, I was quite surprised a couple of weeks ago when I looked in my tank and couldn't find any fish. Well, except for my sucky fish, who is unbreakable. I'd had five little tetras that proved themselves quite sturdy indeed, and they'd lasted forever. I didn't see any fish carcasses either. How could they all just vanish? It hadn't been all that long since I'd last looked in on them. I kept looking through the plants where they like to hide, looking along the bottom, but no fish. None! It was most puzzling.
So I was quite pleased on monday when I happened to glance into the tank. Everyone was back, and swimming around happily! I don't know what happened.... perhaps they were on vacation? After all who knows what pets do when we're not around?
Maybe they went to visit their original owner, because they'd heard she was in the hospital. I think that's what happened in Snoopy Come Home, from my vague memory of the movie. Whatever the reason, I'm just glad they're home again.