Dorsal Fin Communication?

[jmf3460]

My wild discus seem to frequently do this dorsal fin flip thing. Its very fast and fluttery. I do not think it is a reason for concern, rather some type of communication. Does anyone know what I am talking about and can comment? You can see the orange fish doing it in the very beginning of this youtube video. This is not my video, rather just an example I found on Youtube as I don't have a video of mine doing it. https://www.youtube.com/watch?v=v_UuNdt3N5k&list=PLY9de6S_EozD20RNH5qqyYbSffCsCq3Ry&index=33

Thoughts??

[Ryan]

I think it can be both an irritant and a form of communication. I see discus flutter their dorsal and anal fins occasionally, and sometimes their pectoral fins too. Does it ever cause the fish to shimmy or dart? Usually that'd indicate to me that something is irritating them -- water, a parasite, etc. It doesn't always mean you need to take action or treat them. As long as everyone is healthy, eating well, and otherwise behaving normally, it's probably just an irritant they had to shake off. Like when we get an itch.

Usually when I think of discus (or any SA cichlid) communicating with dorsal fins, it involves flicking the fin up and down. They'll quickly lower then raise the dorsal. I've seen them do this when pairing, tending fry, and arguing over territory. They will also flick their pelvic fins in a similar way to signal fry or when facing off against each other.

[jmf3460]

Ryan, thanks for the reply you are a wealth of knowledge. It never turns into a shimmy or dart, nor does it last very long. Sometimes one will do it while swimming towards another one then the one he is swimming towards will reciprocate the gesture. Other times one will just do it while swimming along towards nothing. I also see it most often when one is swimming out from under a limb up towards the surface. Kind of like saying "what up homies I'm here." But I do not see it as something that needs action, I seriously think its a means of communication I just wish I knew what they were saying to one another if that's what it is.