Are My Fish Blind?

[Marco S]

I have five Bartlett Anthias in two different QT tanks currently. Three have been through copper for two weeks then transferred into a clean tank for dosing API General Cure. The other two have not been through copper yet since they looked like they had Flukes and I started API GC instead. Out of the three that went through copper already, two are potentially blind. I say that because all the other Anthias go after the food and get it with the first attempt and these two have to try several times before getting the food. It looks like they cannot see it and just keep biting until they get lucky.

My questions are...

1. Can copper cause blindness in fish?
2. How do you tell if a fish is blind?
3. With what I have explained, do you think my fish are blind?
3. Will this have any negative affects on the fish and it's survival in my DT?

Thanks in advance for any comments on this!!!

Edit: Forgot to add, they did not do this when I first got them. Before the two weeks of copper they ate just fine. That is why I am thinking it had something to do with the copper.

 

[Montiman]

All I can say is I have treated Bartlets with copper many times and never experienced this. Fish can go blind but I have never heard of copper being the cause.

 

[lion king]

I beleive copper treatment can cause blindness, I have had experience with several blind fish and all of them had copper treatment. Back in the day cyanide was also a suspected cause of blindness, maybe even the combination of cyanide caught and copper treatment. Many suspect that cyanide is back in play in the hobby today. Just because every anthias doesn't go blind with copper treatment doesn't mean it doesn't happen. The blindness can be of varying degree, I have stick fed blind fish, and have had to euthanize as well. Check for blindness by seeing if they react to a visual stimulus, your hand to the glass toward them or a stick in the tank in front of their face.