Melafix overdose

[mbuch21]

So I bought a new angel for my 55 gallon saltwater FOWLR. Within 48 hours it started to show signs of stress and fin rot. This was my first battle with it so I tried API Melafix. I probably put in too much as the water picked up its chemical smell... this morning I checked the tank and the stressed fish plus one other angel (otherwise healthy) were dead. A bunch of CUC were dead and the remaining fish and crustaceans were in bad stress. I did a quick major water change and thankfully everyone else seems to have made it. But I was wondering if Melafix is so strong that a modest overdose could kill an otherwise healthy fish and put many others into stress. I read online it is pretty benign so was surprised. I’d welcome any thoughts and experience. Thanks!

 

[lapin]

Its an antibacterial medicine. If it killed enough bacteria then the tank might have an ammonia problem

 

[mbuch21]

Its an antibacterial medicine. If it killed enough bacteria then the tank might have an ammonia problem

You mean all the good healthy bacteria that built up over the past 5 months (since I launched the tank)? I have the nice green film on a bunch of the rocks. Do you think that good bacteria is now dead?