I got this red coris a month ago she acclimated well was eating and swimming everywhere. Not bullying or bullied by anyone. About 3 days ago started to be less active but still eating then swimming in odd ways and laying down to take breaks. Still trying to eat until finally now just laying on the side. Not breathing heavily is this just old age thanks for any help.
This is something that shows up in newly acquired wrasses - usually fairy wrasse, but I've seen it in coris as well. The key symptoms are: odd swimming pattern, but the fish STILL tries to feed. Sometimes the fish lay on the bottom, like this, other times it swims with a curved spine, or dragging its tail. In most other diseases, once a fish begins swimming poorly, it stops feeding at the same time.
It is an unknown peripheral neurological disease...possibly viral, but could also be nerve damage from nematodes or from microsporidians. Since the fish still tries to feed, it is unlikely the brain is affected, more likely the spinal column. or muscle nerves.
In many cases, people attribute these symptoms to a "strike injury", the wrasse running into the tank wall, etc. The trouble with that is these fish never show a bruised snout or other signs that it ran into something. I recently asked a group of fellow public aquarists about this - many of those people have also seen this, but nobody has yet sent a sample our for histopathology, so the cause is still unclear. One aquarist thinks it could be from cyanide collection (since it shows up in more newly collected wrasses). However, the symptoms of cyanide collection in other fish are different. Another curator thinks it is barotrauma from the fish being collected in deep water. Again, I don't think so as there is no swim bladder issues as is typically seen in those fish (and coris come from shallow water).
So, long story short, I'm sorry but we still don't know what causes this, but it is always fatal.
Jay
