fish question

[mlt]

I have a large powder blue tang and a slightly smaller yellow tang. They seem to get along just fine in my 125 gal tank, but
every so often they swim side by side and tap their tails together. Why do they do this? Is this their way of fighting? I also have two tomato clowns one just a little larger than the other and lately the smaller of the two has been making divots in the sand bed and chases the other fish from the corner where it is doing this. Any ideas on why it is doing this?
Thanks and Happy Thanksgiving

 

[mlt]

So does that mean that they are fighting? Or will they get along ok? They have been in the tank together for a couple of weeks and seem ok. Only do this once in awhile. If the clowns are nesting will they lay eggs or bear live babies? Is there a way to save the little ones or will the other fish eat them?

 

[mlt]

Thank you for your help-I wish I had found this site when I first started my tank. When I first started out last March I started with a 55 gal-but for my Bday my husband got me a 125 gal tank and he is now into the fish as much as I am! Thanks to everyone who has heled!