As with many terms that name organisms, this term is often spelled in katakana, especially in biological contexts (where katakana is customary), as タツノオトシゴ. 

 Shinmura, Izuru, editor (1998), 広辞苑 [Kōjien], Fifth edition, Tokyo: Iwanami Shoten
日本国語大辞典 [Nihon Kokugo Daijiten]‎, concise edition, Tokyo: Shogakukan, 2006
デジタル大辞泉 [Digital Daijisen]‎, Tōkyō: Shogakukan
Matsumura, Akira, editor (2006), 大辞林 [Daijirin], Third edition, Tokyo: Sanseidō
Kindaichi, Kyōsuke et al., editors (1997), 新明解国語辞典 [Shin Meikai Kokugo Jiten], Fifth edition, Tokyo: Sanseidō
NHK Broadcasting Culture Research Institute (1998), NHK日本語発音アクセント辞典 [NHK Japanese Pronunciation Accent Dictionary, Tokyo: NHK Publishing, Inc.