This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
鰘 combines 魚 (fish) with 室 (room). The exact historical development is uncertain, but it likely originated as a kokuji created to represent a specific fish name.
A fish 魚 in a room 室: picture a rare fish kept in a special room, but its meaning is unclear.
For ムロア, imagine a muroaji fish swimming in a room: muroa -> ムロア, tying the reading to the fish-in-room image.