Is this unusual?

[Cherie cook]

Yesterday I put two fish in my DT that had been in quarantine together for weeks, a citron goby and a small two spot bristletooth tang. While the goby is pretty oblivious, the tang follows the goby all around every time he catches sight of him! Not bothering him or being aggressive in any way....just like "hey guy so you're here too...how's it going?" He clearly recognizes the goby.

 

[eatbreakfast]

Fish are weird. It's not normal, but not a problem either.