EA Staff (Retired)As far as I know this is the intended design for mermaids and has always worked this way. Hydration is supposed to decrease relatively fast when mermaids aren't in water.
Not sure if this is related, but my child sim mermaids have their hygiene go down with 3 red arrows (ridiculously fast). At first I thought: "well maybe it's because they're a mermaid and the hydration is represented by the hygiene" EXCEPT their hygiene goes down even faster when they are swimming in either the pool or the ocean which is counterintuitive and leads me to believe that this was not intended.
