Now, somehow, their entire mental health is based on the continued life and happiness of this fairground goldfish that they picked up.

Neither of you know the first thing about how to care for even a healthy fish. This fish has been poorly cared for, has multiple diseases and the person who handed it over explicitly didn't expect it to live nearly as long as it already has.

You're frantically googling how to set up a fish tank, where to buy fish food, can you even take a fish to the vet? Your partner wants you to know that they're happy they made it home and survived their horrific ordeal, but also that if anything happens to the fish then they're going to kill everyone on this planet and then themself.

You're honestly wondering if you're even helping the fish, or just prolonging its suffering, but your partner will only accept medical help for their many injuries or engage in basic self-care once they're confident that the fish is being looked after.

So you get a tank. You set up a filter and all that stuff. You learn way more than you ever wanted to know about water temperature and ph and nitrate levels. The fish is safe. You start to develop some affection for the little guy. Your partner begins to recover. The fish begins to recover.

Which is when you learn that in its 'healthy' state, the fish regularly refuses to sleep when tired, keeps begging for food that is obviously unhealthy for it (and struggling to eat the food that you do provide because “it tastes gross”), and continually tries to persuade your partner to take it out of its nice safe tank so it can go explore the wonderful world of Outside, where the slightest mishap will kill it instantly.

“You feel the bulge in his pants” - implies that you are feeling some guy’s penis, may be sexy depending on context

They wear suits, but they don't even know basic etiquette.