Hello, I'm brand new here and relatively new to Betta owning. I have looked up all the care tips and Betta illnesses but I'm presently stumped as to what is ailing my little guy.
I got Flounder (my male Veil Tail Betta) from Petco. He's my first Betta. I know now that pet store Bettas from places like Petco and Petsmart aren't the best place to get Bettas but I just saw Flounder and he was calling to me for some reason. I got him a circular 2.5 gallon tank with air pump and air stone. Up until recently, I had him in there with 2 plants. I took the plants out for fear that if he was sick that perhaps the plants carried the germs of his illness so I tossed the old ones a week ago and have yet to get new ones.
I've had Flounder since Feburary and he's always been a happy fish and very swimmy with his fins relatively flared and open. He had no problems eating or swimming and everything was good for a while. I do water changes about once a week and he never had a problem with those. He rarely ever seemed stressed by water changes. In fact he'd always eat shortly after water changes so I took that as a good sign.
Lately though, he's been laying at the bottom of his tank acting very listless. He still eats but swimming seems to be a struggle for him. He fights his way to the top but then immediately sinks back down.
I feed him Aqueon Betta food pellets and Aqueon Freeze dried bloodworms and I feed him every other day. I only feed him sparsely since I know Bettas are susceptible to bloat and constipation. I will switch up his food... giving him 3 or 4 pellets, skip a day, then give him 3 blood worms, skip a day then back to the pellets.
Since he's began doing this struggle swimming then sinking, I tried fasting him for 2 days thinking perhaps it was an issue of him getting too much food. But that didn't help.
I have cut back to 2 pellets and 2 bloodworms as that's all he can manage to eat mostly because he just can't stay up that long before sinking back down. Like swimming is really hard for him.
This has been going on for about 2-3 weeks now.
I've begun treating his water with API Aquarium salt (1 tsp per water change) and his water is tap water (I live in Los Angeles county) treated with Tetra Betta Safe water conditioner. He also has a heater in his tank and the thermometer says his tank is at a cozy 80.
I'm just freaking out because I don't want my poor little buddy to die. He's such a neat little fish and kinda quirky to me. The only thing I can think of that caused this is that I was out of town for roughly a month (about 3 weeks) and I don't think the person I left in charge changed his water as often as I mentioned as the tank water seemed dirty when I came home. His symptoms started shortly after this.
His skin is clear of fuzz. He isn't suffering fin rot. His scales are NOT protruding/puffed out. Whatever his problem is, it doesn't appear to be external.
Please help... I really need to know what to do from here. He's very dear to me and I feel bad because he was doing so good and now seems to be rather sick. He's a fighter and still eating but it's hard for him. What else can I do to help him get better? I read about possible internal bacterial infections. I've considered treating his water with Kanaplex but I wanted opinions before I involved antibiotics. Thank you so much in advance.
Pictures and video of his current condition
Video link can be found here... You see him sinking down (this was after he battled his way to the top to eat)