First,  always give massages to not stress her out, make sure your mermaid speaks to friends so she has fun and always take your mermaid for daily swims so she can stretch and make sure it hides incase she needs the toilet, by the way its needs loads of toys.

Next, make sure u read fabulous books to your baby mermaid so it can sleep much better also baby mermaids love braids in their hair.

Finally, normally after 1-2 weeks you probably need to bath your baby mermaid so she smells awesome and you can play and meet her baby friends, also u can get a comfy crib.