Why does my bettas tail seem frayed?

Question
I have 3 Bettas who are each housed in 3 separate tanks which are 1 gallon; they have a air filter in each tank, I do not have a filter.  I change their water once every 7 days (never fail).  I notice after I change their water, one of the Bettas tail seems to fray (then mend back that week)  it is only the I fish this happens to.  I am planning on getting a 2.5 tank with the wisper power filter very soon.  One more question:  when I get the new the new 2.5 gallon tank, would a 4 inmch air stone be too much air force?  Thank you very much

Answer
Dear Jackie,
It could be that your one betta that tends to have a frayed tail after a water change could be that he gets a bit roughed up during draining or filling. Some bettas get especially spooked during water changes and can tear their fins on decorations or plants. Bettas can also overexert themselves when flaring at other males or by swimming rapidly itself. Is it possible he has a plastic plant in his tank that has rough edges? Betta's fins are suprisingly delicate.

You may have to do some investigating towards this problem and try to find something different about that betta's tank that could be causing the fin fraying.

I'm afraid a 4inch airstone would be current that your bettas may not appreciate. Airstones provide surprisigly good current in an aquarium and that small of an aquarium is fine for bettas to live in. But I'm afraid the betta may not appreciate the airstone running.

Well, I really hope this helps. For your one betta that gets frayed fins, make sure he doesn't have a plastic plant that could be snagging his fins, or that he is isn't madly dashing around the tank and hurting himself while cleaning.

Only my very best wishes,
Karen~