Wrasse swimming issue

[Biff0rz]

I noticed my ornate leopard wrasse swimming differently yesterday. My wrasse is 5y old, in an established reef, with all fish being purchased qt'd or fully qt'd by me.

Although he was still very active in the tank, eating, mostly acting normal except his swimming which is hard to pinpoint exactly how, but, it's not normal. I did not notice typical signs of spinal injury or swim bladder issues but I did notice some. For instance his tail seemed to droop and be less active when swimming but I did notice him move it. I'm not noticing any abnormal bloating. I'm not noticing any abnormal sinking or floating.

This morning I did see a new concerning issue, when looking at the tank I saw him nested upside down on the sand bed which is not typical for him.

Of course I'm going out of town tomorrow so I have limited time to do anything.

Any advice on diagnosis or next steps to take?

 

[vetteguy53081]

This may be a neurological issue known as UNWD where the fish will be normal at first and then display wierd swim pattern and bent spine associated with origin and method of capture

 

[Biff0rz]

This may be a neurological issue known as UNWD where the fish will be normal at first and then display wierd swim pattern and bent spine associated with origin and method of capture

Is that something that can show up after 5+ years since collection?

 

[vetteguy53081]

Is that something that can show up after 5+ years since collection?

Generally not but then would shift to trauma or similar

 

[Biff0rz]

Generally not but then would shift to trauma or similar

hmm, I noticed his dorsal fin had some trauma -- similar to fish fighting damage. but, in general, this fish has not had any fights with any other fish...nor really any of my fish have. I would akin it to maybe damage from a pump perhaps if anything. But, the trauma didn't look too bad.

 

[vetteguy53081]

hmm, I noticed his dorsal fin had some trauma -- similar to fish fighting damage. but, in general, this fish has not had any fights with any other fish...nor really any of my fish have. I would akin it to maybe damage from a pump perhaps if anything. But, the trauma didn't look too bad.

This is the trauma I was referring to
If there is any new aggression, set phone on video mode and walk away a few minutes next time you feed tsnk
Often aggressor is a jerk at feeding time if this applies

 

[Jay Hemdal]

hmm, I noticed his dorsal fin had some trauma -- similar to fish fighting damage. but, in general, this fish has not had any fights with any other fish...nor really any of my fish have. I would akin it to maybe damage from a pump perhaps if anything. But, the trauma didn't look too bad.

UNWD is almost always seen on newly acquired wrasses. The jury is still out as to the cause - trauma is ruled out in cases where no injury is seen. When you see signs of an injury, trauma is a distinct possibility, and then, how long the fish has been in the tank isn't really part of the equation. Here is the latest write-up I have for UNWD:

Unknown Neurological Wrasse disease (UNWD)​

There is a disease that afflicts newly acquired wrasses, usually Cirrhilabrus fairy wrasses or flasher wrasses, Pseudocheilinus, but occasionally other wrasse species as well. The gross visual symptoms are always the same; the fish shows a rapid onset of neurological symptoms where it either cannot swim well, swims tail down or swims with a bent spine. The other key symptom is that despite those symptoms, these wrasses will still attempt to feed. Most aquarists attribute the symptoms to some sort of injury, such as running into the side or lid of the tank. The trouble with that diagnosis is that these fish do not show external damage (bumped snouts, etc.) that would be expected from such an injury. In addition, the symptoms increase over time and are not immediate as one would expect from a strike injury. Other hypothesis includes barotrauma from deep water collection, or the use of cyanide to collect these fish. The trouble with these possible causes is that symptoms in other types of fish are known, and are different, emaciation in cyanide collection and swim bladder issues in cases of barotrauma. Mycobacterium has also been implicated, but that issue is more often present in long term captive fish, not newly acquired ones as in these instances.

Eventually, the affected fish becomes weaker and either needs to be euthanized or dies spontaneously. To date, there is no known cure, and the mortality rate seems to be 100%. All that can be said is that it is an unknown peripheral neurological disease. It does not seem to be highly contagious from wrasse to wrasse. The causative agent is 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 only the spinal column. or muscle nerves.

2026 update: The working hypothesis in these cases has been some cause other than a strike injury because no external evidence of head trauma is ever seen. However, this was never completely ruled out. From the 2025 histopathology report below, it does now seem more likely that trauma is possibly the cause of at least some these issues. Another researcher had sent some samples out a few years ago to look for a viral cause that had been suspected, but that had come back negative.

Histopathology Report:

Brainstem: Demyelination and degeneration of the caudal brain stem. Three sections of head contained caudal brain stem with areas of demyelination forming two areas with loss of neuropil, multiple exposed swollen axons, and several phagocytic macrophages.

Comments: A cause for the focal degeneration of the brain stem was not found, however, a sharp blow to the head or a clotted blood vessel could result in such a lesion. This lesion was likely responsible for this fish's spinning behavior.

 

[Biff0rz]

This is the trauma I was referring to
If there is any new aggression, set phone on video mode and walk away a few minutes next time you feed tsnk
Often aggressor is a jerk at feeding time if this applies

Yea, I'm not sure where it came from, none of the fish fight even with me away from the tank (video camera's). I'll try and do some more watching to see if I notice anything.

UNWD is almost always seen on newly acquired wrasses. The jury is still out as to the cause - trauma is ruled out in cases where no injury is seen. When you see signs of an injury, trauma is a distinct possibility, and then, how long the fish has been in the tank isn't really part of the equation. Here is the latest write-up I have for UNWD:

Unknown Neurological Wrasse disease (UNWD)​

There is a disease that afflicts newly acquired wrasses, usually Cirrhilabrus fairy wrasses or flasher wrasses, Pseudocheilinus, but occasionally other wrasse species as well. The gross visual symptoms are always the same; the fish shows a rapid onset of neurological symptoms where it either cannot swim well, swims tail down or swims with a bent spine. The other key symptom is that despite those symptoms, these wrasses will still attempt to feed. Most aquarists attribute the symptoms to some sort of injury, such as running into the side or lid of the tank. The trouble with that diagnosis is that these fish do not show external damage (bumped snouts, etc.) that would be expected from such an injury. In addition, the symptoms increase over time and are not immediate as one would expect from a strike injury. Other hypothesis includes barotrauma from deep water collection, or the use of cyanide to collect these fish. The trouble with these possible causes is that symptoms in other types of fish are known, and are different, emaciation in cyanide collection and swim bladder issues in cases of barotrauma. Mycobacterium has also been implicated, but that issue is more often present in long term captive fish, not newly acquired ones as in these instances.

Eventually, the affected fish becomes weaker and either needs to be euthanized or dies spontaneously. To date, there is no known cure, and the mortality rate seems to be 100%. All that can be said is that it is an unknown peripheral neurological disease. It does not seem to be highly contagious from wrasse to wrasse. The causative agent is 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 only the spinal column. or muscle nerves.

2026 update: The working hypothesis in these cases has been some cause other than a strike injury because no external evidence of head trauma is ever seen. However, this was never completely ruled out. From the 2025 histopathology report below, it does now seem more likely that trauma is possibly the cause of at least some these issues. Another researcher had sent some samples out a few years ago to look for a viral cause that had been suspected, but that had come back negative.

Histopathology Report:

Brainstem: Demyelination and degeneration of the caudal brain stem. Three sections of head contained caudal brain stem with areas of demyelination forming two areas with loss of neuropil, multiple exposed swollen axons, and several phagocytic macrophages.

Comments: A cause for the focal degeneration of the brain stem was not found, however, a sharp blow to the head or a clotted blood vessel could result in such a lesion. This lesion was likely responsible for this fish's spinning behavior.

Given this was likely caused by trauma, does that 100% mortality rate still apply, or could it pull through? I'm not seeing any spinning as described. I'll try and take some good video tonight when I get home and share here.

Thing's I've noticed-

• A change in swimming mobility
• Drooped tail, but not 100% of the time
• The tail still moves, but is not as active
• The dorsal fin has some trauma
• The fish was sleeping on it's back, uncovered, this morning
• The fish is eating and active (picking at rocks, for example)

 

[vetteguy53081]

Yea, I'm not sure where it came from, none of the fish fight even with me away from the tank (video camera's). I'll try and do some more watching to see if I notice anything.




Given this was likely caused by trauma, does that 100% mortality rate still apply, or could it pull through? I'm not seeing any spinning as described. I'll try and take some good video tonight when I get home and share here.

Thing's I've noticed-

• A change in swimming mobility
• Drooped tail, but not 100% of the time
• The tail still moves, but is not as active
• The dorsal fin has some trauma
• The fish was sleeping on it's back, uncovered, this morning
• The fish is eating and active (picking at rocks, for example)

Prognosis not positive and I e seen low recovery from these scenarios

 

[Jay Hemdal]

Yea, I'm not sure where it came from, none of the fish fight even with me away from the tank (video camera's). I'll try and do some more watching to see if I notice anything.




Given this was likely caused by trauma, does that 100% mortality rate still apply, or could it pull through? I'm not seeing any spinning as described. I'll try and take some good video tonight when I get home and share here.

Thing's I've noticed-

• A change in swimming mobility
• Drooped tail, but not 100% of the time
• The tail still moves, but is not as active
• The dorsal fin has some trauma
• The fish was sleeping on it's back, uncovered, this morning
• The fish is eating and active (picking at rocks, for example)

The mortality rate for this issue is pretty high - 100% of the cases I’ve had in hand. However, injury is still not the certain cause of this, so your fish may recover.

 

[Biff0rz]

The mortality rate for this issue is pretty high - 100% of the cases I’ve had in hand. However, injury is still not the certain cause of this, so your fish may recover.

Here's a video of the fish. Let me know if you notice anything abnormal. You can see the damaged dorsal fin.

 

[Jay Hemdal]

Here's a video of the fish. Let me know if you notice anything abnormal. You can see the damaged dorsal fin.

The damage is very far back. In the case where the damage was noticed histopathologically, the damage was up near the head.
Perhaps the wrasse got bit, and that in turn startled it into hitting something in the tank headlong?

 

[Biff0rz]

The damage is very far back. In the case where the damage was noticed histopathologically, the damage was up near the head.
Perhaps the wrasse got bit, and that in turn startled it into hitting something in the tank headlong?

I suppose that's possible, I really have no idea what would have nipped at him. Of all the fish to tussle, its not the wrasse I have. The tangs swat at each other, but, it's occasional and infrequent.

 

[Jay Hemdal]

I suppose that's possible, I really have no idea what would have nipped at him. Of all the fish to tussle, its not the wrasse I have. The tangs swat at each other, but, it's occasional and infrequent.

Sorry, I don't have any ready treatment for you to try. Just supportive therapy: ensure the fish keeps feeding enough to maintain body mass and see if it can heal, and watch for any tankmate aggression.