Something Sharp In My Tank?

My Betta's fins have quickly been getting really ripped. I'm not sure why. I have a plastic plant but it is quite soft and is rounded at the edges so I thought it would be fine. Could he be ripping his own fins?
One thing is that my filter is an old whisper filter and it has an intake in the back.
He is acting happy and healthy and just a few days ago is fin where healing and looking very good (Rescue Betta recovering from fin rot.) Best bet for me is the filter. What is you're opinion.
Oh and it started after I did an Epsom salt bath. Don't know if that could mean anything.

 

Did you sand the holes on the white rock thing? I was thinking about getting one of those today until I felt the edges of the holes...didn't geel like all that sanding today

 

No I probably should. He never seems to swim through them though. Better safe then sorry! I'll try and do that first thing tomorrow and see if it works. Thanks.

 

Did you sand the holes on the white rock thing? I was thinking about getting one of those today until I felt the edges of the holes...didn't geel like all that sanding today

I almost got one of these rocks, too! I felt they were too sharp for my bettas and angelfish, though.

 

I almost got one of these rocks, too! I felt they were too sharp for my bettas and angelfish, though.

I really like it though, and have some sandpaper out in the garage. Just wasn't feeling it today. I think it would look really good in a tank or two of mine

 

I really like it though, and have some sandpaper out in the garage. Just wasn't feeling it today. I think it would look really good in a tank or two of mine

Yeah, it's different than normal rocks. It sort of looks like a dead coral from the ocean. I only skipped over it because it was sharp, and didn't know you could take some sandpaper to it!

 

Yeah, it's different than normal rocks. It sort of looks like a dead coral from the ocean. I only skipped over it because it was sharp, and didn't know you could take some sandpaper to it!

Yeah, I sand most things I put into my betta tanks.

 

I'd bet it's the filter. I had the same one with male betta (before I knew about sponge filters) he was having fin issues then one day I caught him stuck to it with his fins being sucked in. I freaked out, and ordered a sponge filter. Panty hose works over the intake until you can get something else. He could be getting behind the filter because the flow is low there and having his fins ripped.

 

Yeah, it's different than normal rocks. It sort of looks like a dead coral from the ocean. I only skipped over it because it was sharp, and didn't know you could take some sandpaper to it!

Yeah I think it looks so cool. I love it and I would hate to have to remove it. It was a bit of a rushed buy, I had two fish in a car. Outside it was probably like 40 degrees and it was a Walmart far away from me. I was worried I wouldn't be able to find it again. So I wasn't really thinking. I didn't even think on sanding it. Newbie mistake on my part.

I'd bet it's the filter. I had the same one with male betta (before I knew about sponge filters) he was having fin issues then one day I caught him stuck to it with his fins being sucked in. I freaked out, and ordered a sponge filter. Panty hose works over the intake until you can get something else. He could be getting behind the filter because the flow is low there and having his fins ripped.

I'll see if I can find some pantyhose I might also try a putting a sponge on the intake. I'm already thinking on getting my other Betta a sponge filter because she gets really stressed with even a little bit of current.

Thanks for all the advice!