Bflynn – I’m sorry about your Chromis and I can’t help with an explanation but I was really interested to hear Fanlie’s story about his Chromis going blind. I had exactly the same problem with the six Chromis in my tank. When the first one disappeared I put it down to the bullying issue that many people had reported, although I had never seen it in my tank. Then the second one disappeared. And then the third. While looking for the body, I found the fish hiding under a rock looking quite disoriented - seemed to be bumping into things. Two days later it was gone and I presumed it died but I have a 1.8m tank with lots of rock so I wasn’t surprised to not find a body. I started paying more attention to the behaviour of the other three but all seemed fine at this stage, as were all the other inhabitants (clowns, goldies, tangs, etc.) Then I noticed one of the remaining three stop eating although he was swimming through the food as it was added to the tank and occasionally snapping at a piece. On closer observation it became clear that the fish was blind – it was swimming very slowly and actually swimming into the rock work. The fish was still alert and when I put a net into the water and he touched it he certainly reacted and swam away. But If I put net in front of him he just swam into it. Eventually, exactly the same thing happened to the last two. The strange thing is that it didn’t happen to all the fish at the same time – it happened over a period of about six or seven weeks. There was no cloudiness of the eyes that I could see. I don’t think it was some form of toxin as I would have expected the other species to also have been affected or, at the very least, all the Chromis to have been affected at the same time. The fish were acquired from two different shops, but at the same time, so it is possible that they could have been part of the same import shipment. Still don’t know what caused it but one possibility (although I have no proof of this) is that the fish had been caught using cyanide – I have seen on other sites that members have reported that blindness is one of the symptoms shown by cyanide-caught fish.
