Harlequin Behaviour

[Ny82]

Hi folks, well I have a group of 9 harlequin rasboras in my tank. They seem to have gone off into little groups.
I have 5 who all swim together-one skinny one (male?) and 4 plump ones (females?)
I have 2 very small ones the size of endlers who get chased by this group if they try to swim with them.
I also have 2 bigger ones  who are swimming in perfect unison side by side around one of the plants then suddenly hit off each other. 
Are these behaviours just establishing pecking order? Are the 2 who hit off each other males and fighting for dominance? I am starting to worry as I read they were peaceful fish!
I also have a male guppy who is trying to mate with all of them but that's a different topic

 
Thanks for the help.

 

[b3cca]

Lol idk, but it's the same as my harlies do.
 
5 of them usually stick together and the other 3 seem to just go do their own thing and hang with my gouramis or cherry barbs. 1 little fella is like the lone ranger he always does his own exploring, but strangly he seems to be the most active and the happiest so i leave him to it.
 
I think if they feel comfortable and safe and realise there is no danger or predators in there then some don't feel the need to school together so much.
 
As long as they are eating and don't seem scared or stressed I wouldn't worry as mine do the same thing.

 

[PlumbersMerchant]

Yeah, harlequins are lovely. Ive recently found lately (via another thread on here) that there are 3 very common types of Harlequins that are continually labled as rasboras. Im wondering if they are possibly different species and stick to their own kind ?
 
Saying that tho, i Bought four to start with, then as i got more and more into the hobby and my tank got more mature i added another 2 so each fish type has 6.
 
Long story short, i think mine are 2 different types of harlequins sold to me as rasboras but they still school occasionally. As b3cca says, Schooling only really seems to occur when the fish feel danger.
 
Hope my 2 pence helps ?

 

[And76reW]

The espei rasbora (lambchop) is very similar to the harlequin, difference is that the espei is a red colour rather than orange. Beautiful looking fish, my lfs has them & I will get about 4 of them to join my 3 harlequins.