Blue Chromis behavior

[Neoz]

I have 5 Blue Green Chromis. I have one doing something i haven't seen them do before.

The same Chromis keeps going down to my sand bed. While he is down there he like ruts in the sand with his belly and kicks up a little sandstorm with his fins. The whole time doing this his dorsal fin (I think its called) is arched right forward not laid back like usual. Does this for a few seconds then proceeds to swim. He looks fine as does the others. Is this normal for them? Some kind of mating thing or what?

 

[nwrogers]

Not sure if that is a mating thing. Some clownfish do that I think but I don't know why. I had a chromis that displayed frequent mating behavior. What the fish did was to go over to the overflow and rub its underside all over. It was also paired with very aggressive sharp swimming. Very cool to watch...

 

[Neoz]

Same thing mines doing only using the sand. It is cool to watch. Especially the aggressive swimming. Although I could do without the mini sand storm.