Betta Fish With Mouth Stuck Open

HI everyone

Last night I saw my betta fish playing around with the bubbles from his sponge filter (like he was trying to eat them as they rose to the top, very aggressively). He's never done this before so I thought it was strange, but he soon left so I didn't bother doing anything.

Later I saw his mouth was wide open and he isn't closing it. He attacked the bubbles again, so I turned them off in case this was the cause. After that he would stay still in a spot and "thrash" around against something (rock decoration / tank wall, etc.), like a dog wagging its tail, but a fish wagging its body. He also comes to the top of the water to get air A LOT more than he normally does.

He didn't want to eat when I went to feed him, nor did he come up to see me when I go by his tank, as he always does.

I performed my regular weekly water change earlier that day (yes, conditioned water) but the temperature was probably a bit higher than his tank (4 degrees ish?), but it was only a 20% change so it probably wouldn't have increased the tank temperature significantly. Thermometer is always reading 78 F, but I didn't check it shortly after adding the new water.

Another thing I thought might have been the cause was I was staying up pretty late, and normally turn off his tank light at 9:30pm, but forgot and this was at 11:30, so he might have been sleepy and cranky? I turned his light off and let him sleep.

This morning his mouth is still open, and will not eat or come to the edge of the glass to see me again. He is mostly hiding around his plants. He is flaring a lot and sticking his gills out (?)

Something I also noticed was the tips of his fins were a little "bent" at the tips (he is a crowntail). I'm not sure how long that was been on for, but I added a new fake plant along with the water change, so I took it out in case he was getting cut from it (but I had this plant in a couple of months ago with no issues).

Tank parameters were good, except pH was a little low so I added some pH up.

I can't see anything inside his mouth, but its hard to get a good look since he's hiding in the plants.

Here are some videos:
HI'm in the bubbles:
After I turned the bubbles off, can see him flaring and opening his gills:

I've tried looking around in other forums, but found nothing that helped really.
Anyone have any ideas? Is he choking / can he breathe? Is he sick? In shock?

Tank information:
5 gallons
1 male betta
1 mystery snail
Heater
Sponge air filter


Sorry for the novel, I'm just really worried about him and want to give all the information I have, I love the little guy
Please help and thank you for reading

 

Something I forgot to add: sometimes he blows bubbles at the top of the water. I'm not sure if he's just trying to get some air, or what he was doing. Didn't really look like he was trying to build a bubble nest, but I have never seen him build one.

and I got him at the start of May (2 months now). No previous issues with him.
He mostly gets along with the snail, but sometimes will flare at her if she goes near the top where he eats

 

I know bettas yawn but not sure what this is. I've been seeing the weirdest post about weird things bettas get or do. Like a betta getting a tumor. So many things I have never experienced or even thought could happen to them.

 

I know bettas yawn but not sure what this is. I've been seeing the weirdest post about weird things bettas get or do. Like a betta getting a tumor. So many things I have never experienced or even thought could happen to them.

Thanks for the input, I went to the store and got some all in one infection treatment. If it doesn't help with his mouth, it might help if his fins are cut anyway.
I removed the snail because he was being very aggressive this morning. Seems to have calmed down now that he's alone.

 

He's coming to see me when I approach him now. Still won't eat though.
Here's a close up picture. You can see at his mouth open and his bottom fins the tips are bent. Anyone know if they're cut or damaged?