R + C

As promised, yunc & I will go some fish shop today.
We had also decided to buy at least 6 small
Peacock (Chinese) fish for some room decoration.

That time was about to reach hot sunny noon.
I was just awoke and got 2 missed call from yunc.
"Hmm, where she goes?", I was wondered.
When I wanted to call her that time, she'd return home.

Now only I knew she "put me an aeroplane"
and went to a fish shop alone.
She had bought back a pair of fish instead of 6 (six).
We placed the fish into a mini-bowl with some grass.

After a few minutes, they started to woo each other.
They looks happie in their new mini home everyday.

Seems it's a pair, we've named them "R" & "C".
Guys, guess which one is male & which one is female?

Which is "R"?
Which is "C"?

The photo above will give you a hint.