鱼只有七秒记忆七秒全部都是你
[yú zhĭ yŏu qī miăo jì yì qī miăo quán bù dōu shì nĭ]
Fish are often considered to have only 7-second memories; so when saying these seven seconds are filled with thoughts of just one individual, this indicates undying and consuming adoration toward someone, meaning every moment of attention is solely occupied by thoughts of the lover.