Angel dead..

[Fisshboy]

Hi all, woke up this morning to find one of my Angel fish was dead. Had no sign of any disease or anything was fine and healthy last i saw it last night and no sign of been bullied, tested my water and it was Ammonia-0ppm, Nitrite-0ppm, Nitrate 20ppm, PH-7 and temp is 27C all filters and stuff running like normal im a little baffled as to what happened to it does can anyone shed any light on my situation?

Thanks in advance

 

[spiketooth]

How old was the angelfish? Maybe it was his/her time

 

[Fisshboy]

Iv only had it around a month was no where near fully grown, it was about and inch and a half square in size

 

[spiketooth]

Guessing he was sick and just didnt show any signs, it does happen