freshwater problems

[Nano]

Also. Imo

Ditch the top fin and cheap foods. Get some new life spectrum or new era either flake or pellets (preferably pellets) top fin and nutrafin etc (walmart cheap brands) tend to add a high ash content to they're foods as well as a ton of fillers which aren't generally good for the fish. You'll see better results with a good food. Though I doubt that's your problem right now, I found new life spectrum and new era to give my fish vibrant colors less poop and generally more active.

[SanguinesDream]

If your only going to do a 50% water change, stuff in a new carbon filter to pull the heavy metals out of it. Personally, I'd do at least a 75%wc with RO water and still pushing a new carbon filter.