Danios Flaring Fins

[TPIRman]

Hi all --

A big day for my 10-gallon tank, stocked with 7 danios (various species). Went to the LFS to get some aquatic plants -- Amazon sword, Cryptocoryne wendtii, and Ludwigia repens -- and also got some live food -- blackworms, rinsed thoroughly etc.

After installing the improved aquascape and dropping in a few clumps of delicious worms, the fishes were quite excited. Once the feeding was dying down a bit and the fishes were hunting through the gravel for the remaining worms, I noticed a couple of the zebra danios flaring their fins out very stiffly and acting territorial -- when the two got close to each other, they got into little tiffs (definitely different from the usual games of "tag"). Finally the smaller zebra's fins dropped down, but the larger one kept his fins up for quite a while.

This evening I did a water change, and the bigger one is again in "flag" mode. It's quite beautiful, and as far as I can tell, nobody is getting hurt, so I'm not too worried. But I am curious as to what is going on -- everything related to fin-flaring that I've read is in regard to bettas.

Thanks in advance for any insights you might have.

-John

 

[Tetratastic]

That sounds cool! Assuming no one's getting hurt of course I've never heard of danios flaring before, are yours long finned or short?

 

[OrionGirl]

Fin flaring is a common display from most fish, though most easily seen with the labyrinth fish (mostly bettas and paradise fish, but gouramies as well). With danios, is most often the females (larger, rounder) that display. It's very noticable in the long finned varieties, but the short fins do it as well. I never had problems with them hurting one another, but they displayed often.

 

[TPIRman]

Tetra -- it is cool! All of my danios are short-finned (I like the sleek look) except for a couple longfin blue danios.

Is the fin display a mating display or just something they do when they're feeling good?

 

[OrionGirl]

Like most social fish, there is a hierarchy for the group. The dominant fish will display to show how tough and cool it is, and challengers will display to, well, challenge for the dominant position!