Hello...woke up this morning and found my much loved oscar floating on the tank surface dead. Why..I don't know. He has been eating fine, his tank mates are 5 silver dollars and a texas. Water is changed on a regular basis. Water readings are amm 0, nitrite 0 and nitrate 5. He has a small showing of hole in head which I have treated but it looked very minor. Nothing else to tell really. Its a bit of a strange one! He was only about a year and a half old, fishing him out, he weighed a ton! Any suggestions as to why would be appreciated.

RIP Ozzy.

Hmmm I'm not quite sure but the fact that he had HITH in very clean water suggests something a bit fishy. What exactly are you feeding him? Tank size? Filtration???

He was in a 400 litre, 2 externals, a Fluval and a Eheim. Plenty of media. Food wise, he had quality pellet, worms, bloodworm and sometimes beefheart.On close inspection, his eyes were almost popping out his head. Related or not I dont know?

So sorry for your loss! RIP Ozzy...

RIP Ozzy!

I suspect he probably had underlying problems that just weren't obvious to you. The water has to be pretty dire conditions before actually kills a fish without you seeing any symptoms first.

People who keep very expensive ornamental fish would have probably had an autopsy done on a dead fish if they didn't know what caused the fatality, however that probably isn't feasible in our cases.