I'm Not Fat! My Tail Is Just a Little Short!

As one of the heirs to the wealthy Zhang family, Zhang Jingyang grew up in luxury. Sadly, neither his father nor his mother cared for him, and he grew into a cold and heartless man. Then one day, he found an injured little mermaid in his swimming pool and got his hands on a Guide to Raising Short-Tailed Mermaids... During the day. Little mermaid: Hah! I can take on three weak Earthlings like you at once. Evil stepmother: Aaaaaah, a ghost! Horrible stepbrother: Aaaaaah, help! Snobbish servant: W-we've got a poltergeist! Assistant Liu: ??? At night. The little mermaid, wearing bear pajamas, timidly knocked on Zhang Jingyang's door. "Big brother, I'm afraid of the dark. Can I sleep with you?" Not long after. Assistant Liu said to Zhang Jingyang with trepidation, "M-Mr. Zhang, I suspect Jiayin has antisocial personality disorder QAQ" Zhang Jingyang: "Oh." The little mermaid, who had suddenly appeared from who knows where, gave Assistant Liu a sweet, innocent smile. Please note: * An overpowered golden finger * Mpreg, mutual pampering, maximum wish fulfillment * Devoted top who caters to every whim × bottom with overwhelming combat prowess