what the heck

[onthecourt4life]

I just lost a watchman goby and i am wondering why. I am doing test right now.
He had one grey eye and looked like he was forming like a white band around the middle part of his body. Any ideas on what this could be? sry about the lack of details and i couldnt get a picture becuase he was getting eaten by the clean up crew. Also i was told about the symptoms by my little brother thats 12. i will post my test results after im done testing.

 

[onthecourt4life]

everything tested out well sg 1.023
temp 80
nitrite 0
nitrate 10
ammonia 0

I was wondering i think my heater has a crack in it. i think this is what cause the fish to die. i think it got burnt and took in some bad stuff. My coral is doing great, so if my heater was cause the fish to die would my coral still be doing well?