What’s my Royal Gramma doing? Video attached.

[3000kelvin]

My Royal has been in my tank with the Yellow Watchman for about 2 months. I have a clown pair as well. The Royal has been very peaceful and the only aggression I’ve seen is between the clowns. Anyway, my Royal started doing this to my Watchman this morning. It’ll swim up to the watchman with an open mouth. No biting but it looks like an aggressive move.

 

[j.falk]

That's how they defend their territory. They'll puff their mouths out to look bigger/more threatening to scare off intruders. Mine used to do it all the time to my clownfish. They just ignored him and he eventually stopped doing it.