Holes in fins - fin rot or something else?

[Stellafish]

I got Salvador about a month ago. When I got him his fins were perfect except for one small hole in his bottom fin. He continued to be fine for about two weeks when all of a sudden one morning his fins were shredded; I think he had gotten fin rot, although I was surprised at how sudden it was. After a week of salt baths and daily Betta Fix, I did an almost complete water change as per the instructions. His fins were healing just fine. He continued to look fine until I got home from work today and now, he has three huge holes in his fins. The original hole, which never healed, is now bigger, plus he has a big hole in his tail and one on his top fin. It looks different than the fin rot I have seen before, but I'm not sure what else it could be? My long-lived previous betta never had holes like this. I'm worried because he has been doing so well but I don't want his poor fins to be in such bad shape! But I don't want to start him on another medicine regimen if that's not the problem, since personally I think the medicines can be stressful on them. He's a VERY active fish (when they put him in a cup at Petsmart, he jumped out!) and his activity level/hunger hasn't decreased, so I don't think he's feeling bad.

Background/info: 5 gallon tank by himself, kept at 78 degrees with heater, filter, fed betta flakes and sometimes bloodworms, tank is fully cycled, I do 25% water changes weekly normally, did salt baths with 1 Tbsp salt/gallon for 15 minutes

I've attached some pictures where I tried to capture the holes; you can also see his recovering fin rot. Thanks for any thoughts/advice!

[Oldfishlady]

It may be damage from the filter water flow/current and/or over use of the fins-sometimes the delicate fins, especially if compromised already...the water current can be the cause along with just the process of swimming...use of the fins....it sometimes can be a switch off...between keeping nice fins and giving the Betta more room and filtration....a bit like a flag blowing in the wind effect to a degree.....

What I would do-is just provide quality water-increase your water changes to 1-50% weekly with vacuum and 1-50% water only a week...to prevent secondary infection....you could also remove the filter and see if that makes a difference....

We want to provide more space for our Bettas...sadly, sometimes it comes with a price....delicate fins.....not all but some.....

[Stellafish]

Update: I came home from dinner like 3 hours later and his fins are completely shredded! I am horrified! The filter is very low flow... it doesn't even make bubbles... so I don't think it could be too strong? Eeek! Posting updated pictures... see the extensive shredding??

[scootshoot]

I noticed my male betta with a small slit in his fin (sort of like your pic). Within two days it naturally healed / closed up. He loves swimming close to the roots of his java fern (which is not buried under the gravel) so he probably got himself slightly caught....

[Pekemom]

How's he doing today, Stella?

[peachesxo]

is there a plastic plant or something in his tank he could be tearing it on..?