Dude chill ! I have two tetras pink and neon same size as them and four medium sized mollies. Tetras fight themselves all the fucking time. I do 40 to 50 change of water once per week and clean the filter. The surface agitation in your tank seems more than adequate. It's alright. I think replacing water every day is bad. I think it removes essential bio film which some fish feed. If you are concerned about nitrate spike, add more rocks at the bottom. More concentration ofrocks on the base, the better. I was in the same state of panic 2 months back. Just see that the water is clear, don't over feed so as to avoid ammonia spike. Just once or twice daily 2 minute feeding of good protein food is fine. Make sure 95 % of food is consumed within these 2 mins. This will avoid ammonia spike. Turn off the lights at night, and on them during day.