Guppies Eyes Have Turned Black?

My Guppies all had Black eyes but with a yellowish rim around the outside then today 5 out of 6 of them went pure black, then a few hours later, there are just 2 with black eyes is this normal or is there something wrong?

Is the tank cycled? If the tank is not cycled I would do a 25% water change. The eyes turning jet black can be attributed to poor water quality or if the guppys are at a young age then they could have turned black because its there true color of there eyes.

My guppies which i've been breeding for 5 year from a moscow line cross, have black eye's. Always have and always will. this is shown over several generations.

I'm sure it's just colouration and nothing hasty you have but keep an on them and report back if you have any problems.

they seem to be ok but there eyes are chabing quite alot from black to normal and back.