Betta is Sick??? Lost
Around Tuesday, my betta started laying on the bottom of his tank or hiding in plants, not eating. He'll come up to breathe every so often but then will go right back down. He wasn't on his side and he wasn't breathing heavily until about yesterday (and every so often he'll breathe normal again). His coloring is fading /badly/ and he's got no energy when he'll usually follow me around the room. He's not bloated and I don't see any parasites or fungi. There's a little discoloration on his gills??? Or they looked inflamed but I don't know from what. I /just/ went to look at him again and now he's upside
About him: he's a koi betta and I got him at the end of August 2016. This is the first time I've had any trouble with him. His diet is a mix of freeze-dried brine shrimp and the tropical flakes that usually come with the tank(I try to break it up in smaller pieces for him).
It's filtered (sorry I don't remember exact details for it but it's for a 10g or more)
Nitrate: 10ppm (maybe 20ppm but definitely no higher)
I know pH is high but that should be doing this should it? The only other thing I can think of is his diet but. Am I missing something??? I don't know what to do. He is in rough shape