So I have a 10 gal freshwater tank which I believe is fully cycled (although I don’t 100% trust my testing strips), I’ve had it for a couple months. There is currently only 1 pearl danio and 1 white tetra in the tank, both of which I bought and put in at the same time 2ish weeks ago. I noticed the tetra had a piece of her top fin missing last week, so I removed the agressive zebra fish that I thought had nipped it. In the past couple days I’ve noticed that fin now has a reddish tint at the base. She was acting weird, hiding and not eating yesterday. Today she came out finally to eat and she looked like this (see pic) with the red spots on both of her sides. Any thoughts?? Side note— the pearl danio is acting normal but I’m fairly certain that the black spot on his top fin is new. I’m pretty new to fishkeeping and have never dealt with any illnesses. I do 25% water changes every other day (sometimes with a gravel vaccuum) and use water conditioner and quick start with each change. Help please!!