u/Opposite_Meringue_69

Hi everyone so I’m posting on behalf of my boyfriend, he has a 25-30 gallon cube tank that’s been going for almost a year. He has a Purple Fire Fish that hasn’t been doing well- I’ll post the photos of him. He dosed the tank with Melafix this morning. Unfortunately he doesn’t have a quarantine tank so we don’t have somewhere we can move him to be alone. All water levels are fine, he’s been checking. If anyone has any suggestions we would really appreciate it 🐟

EDIT: Heres water levels: Ph 8.2-8.4, KH 6.5-7 dosing daily, Ammonia 0, Nitrite 0, Nitrate 26.5 (elevated, water changing down to 20), Salinity 1.026, Temp 78°F, Magnesium 1400, Calcium 400, Phosphate .07
He’s sluggish and breathing hard, back body curls upwards, he’s eating.