Angelfish not eating

[Kqiu2006]

One of my angelfish (6 month) has not been eating anything for several days. What would be the problem? Is there any cure for that
Thanks a lot

[exv152]

Is this a freshwater or saltwater angel?

[Kqiu2006]

Freshwater

[exv152]

Have you tested the water parameters? What is the temperature? Is the fish behaving differently - hiding, loss of colour, is he being bullied by tankmates etc?

[Kqiu2006]

Water temperature is 80F. Have not tested water parameters. The fish does hide and is losing color slightly

[exv152]

I'd suggest testing the water quality to make sure there's no ammonia and nitrites (not nitrates) to eliminate the common toxic elements first. If there's any present you want to do a large water change to ensure it's not environmental. Then move on to rule out health issues like bacterial, fungal, viral, or parasidic infections.