Help needed: New boi has been gasping/panting for over a week. What's wrong? (video)

Video of him panting/gaspingMy new fish has been panting/gasping for air. I just got him less than three weeks ago (10/18) from a woman who bought him from Petco a month before. He appeared healthy when I got him except that he has an unusual ridge on his torso, like a horizontal line running through the back half of his body towards his tail, and can be seen from both his left and right sides. This ridge didn't seem to impact his ability to swim. He was acting happy in his new home with me and even built a bubble nest his first night and the following days.About ten days after I got him (10/28) he stopped eating for a day but was still active. Once he started eating again I noticed he was gasping or panting. Last Friday (10/30) I did a 50% water change. I trimmed back the plants in his tank, figuring he would appreciate more room to swim. He didn’t seem to like that, and for two days he thrash-swam around his tank, gasping. For the past couple days he has calmed down, still eating like normal, but also still gasping. He will alternate between swimming and resting.I took water parameters on Monday (11/02) and again today (11/07) and the parameters were the same each time. The pH is on the high side (7.5) but I didn't want to accidentally change the pH dramatically by messing with it.Any thoughts on why my guy is having a hard time? Thank you!​Tank size: 5 gallon Fluval Spec V.Heater and filter? (yes/no): Yes.Tank temperature: 80 degrees F.Parameters in numbers and how you got them:I tested on 11/02 and 11/07 and got the same results.pH: 7.5Ammonia: 0ppNitrites: 0ppmNitrates: 0ppmAPI Freshwater Master Test KitHow often are water changes? How much do you take out per change? What is your process?: Every other week I do a 30-50% water change using a gravel vacuum, and I rinse off the sponge filter and inserts. Once a month or so I removed rocks, plants, and other accessories to clean them. The snails and shrimp help keep things clean.Any tankmates? If so, please list with how many of each: 4 neocaridina shrimp, many juvenile ramshorn snails.What do you feed and how much: Hikari Betta Bio-Gold (4 pellets twice a day) OR Fluval Bug Bites Betta Formula (equivalent of the former), and Tetra Freeze Dried Bloodworms as an occasional treat.Decorations and plants in the tank: 3 anubias on wood, smooth frogbit, and some unknown moss. Golden Pothos growing out the top of the tank. Betta log and Indian almond leaf cave for hiding.If you haven't already posted a picture, please post pics/vids to imgur and paste the link here: Photo of my tank. via /r/bettafish https://ift.tt/3lbTwwl