鱼的记忆只有七秒我的七秒里都有你

This username translates to 'A fish's memory only lasts seven seconds, but all my seconds have you'. It conveys that despite a fish’s very short memory span (seven seconds), the user feels like they can still remember or think about a certain person every moment. It's poetic expression symbolizes strong feelings for someone, almost like love at first sight where every fleeting moment is precious.