'dancing' Harlequin Rasboras?

[xamy_valox]

Hi there,
Last night I was watching my tank and 2 of my 4 Harlequin Rasboras were doing a strange little dance! They were staying very close to each other, literally side by side so it looked like one fish, then kinda shuffling backwards breaking free and then joining back together again?
I've seen them do this before but not for as long as last night, I don't know if it's a mating thing? Though I have never seen any eggs?
Also as a side note, when I was looking I also noticed one of my little panda cory's back fin was quite badly nipped, more or less all of the top of the tail fin was gone! I have no idea what has done this but he is acting fine and going about his business as normal, will it grow back again though? I know fishes fins normally grow back over time but I wasn't sure cus of how much has dissapeared!
Thanks, Amy xx

 

[soybean]

My harlequins do this, they're displaying to each other.

Cory fin should grow back. Keep the water very clean. I had a platy that used to go for cory fins when she wanted their food. Tetras can be nippy too.

 

[xamy_valox]

How do you mean displaying? In a breeding way or aggressive?
Amy xx

 

[soybean]

In a natural way. All to do with breeding really. Males display to each other to establish pecking order and who wins the females. Or males display to females to impress them. They shouldn't cause any damage. I like watching it

 

[xamy_valox]

Ahh good, as long as there's no fighting! My rasboras are probably the most placid fish I have other than my cory's! Yeah it was interesting to watch, I think I'll enjoy it more now I know what they are doing!
Thanks!