Help My New Betta!

[guppy2002]

I just got a new betta about a week ago and he was doing just fine. I set up a filtered 7.5 gallon for him. A couple days later  I saw a small rip in his fin, so i took out the plastic plants in his tank and replaced them with soft ones. A few days after that, almost all of the white on the tips of his fins was gone! Heres my ideas of what might have happened:
*the soft plants could still be ripping his fins (they are in the second video)
*the filter could be too strong. I have seen his fins get stuck to the filter sometimes.
*there are two guppy fry living with him, though they are only about a centimeter long, they could potentially be nipping him.
 
all of the rips seemed to appear overnight, or close to it.his name is Tai, by the way. here are the before and after vids:
 
Still in the cup
www.youtube.com/watch?v=QIG_6lpMHTU&list=UUJ8ci5MfAZNkk4-LJxptMmw
 
  In his tank, with plastic plants
www.youtube.com/watch?v=V83AyW3hk2E&list=UUJ8ci5MfAZNkk4-LJxptMmw&index=2
 
him currently
www.youtube.com/watch?v=333LtaRyH9U&list=UUJ8ci5MfAZNkk4-LJxptMmw&index=1

oops, those weren't links. here they are
http/www.youtube.com/watch?v=QIG_6lpMHTU&index=3&list=UUJ8ci5MfAZNkk4-LJxptMmw 
http/www.youtube.com/watch?v=V83AyW3hk2E&list=UUJ8ci5MfAZNkk4-LJxptMmw&index=2
http/www.youtube.com/watch?v=333LtaRyH9U&index=1&list=UUJ8ci5MfAZNkk4-LJxptMmw

 

[EllieJellyEllie]

First off, videos are private, I cant see them. He may be tail biting, which you cant really stop

 

[guppy2002]

does it work now?

 

[betta fish]

Hi, just seen the vids, if you have noticed this suddenly I very much doubt the guppies did it, it looks rather extreme, I would suspect he did it himself due to some type of stress, the filter does seem to be pushing him about a bit so I would first off cut the flow a bit. I would also remove the guppies if they can go elsewhere for now as they may be stressing him and keep the water really clean with regular water changes and the fins should grow back, what temp are you keeping him in? perhaps some Indian Almond leaf in if you can get it the tannins should calm him a bit, he is lovely btw 

 

[Mamashack]

Tai does seem a bit agitated in the 2nd video. If it was the filter tearing his fins it would be irregular, but it seems like all the butterfly stripe has gone completely, which would make me think of tail-biting too. That could be stress as betta fish said.
Did you cycle the tank before putting him in? 
What are your water parameters?

 

[majerah1]

Tailbiting for sure. The filter is too strong, most likely a stressor. I suggest looking for a sponge filter. Would be much easier on him and just as effective in filtration. 
 
Water params would help as well