Brain damage ? (videos)

[magnus]

Hi!

I have recently had some bad experiences with several fish from a particular LFS. The fish is usually quarantined by the LFS for one week only before I pick it up. After normal drip acclimation and installation in my QT, the fish appears to be perfectly healthy and eat what I normally feed new fishes (mysis) right away. Then after 5 to 10 days in QT the fish start to move strange, as if it has a brain injury or possibly eyesight or balance disorder. The fish still react to food but fails to catch it since it have increasing problems to control its movements. This leads to the fish starves and eventually dies. I can see no external sign of anyting wrong except it's getting thinner. Breathing seems normal.

My QT is around 20 gallons and I do 50% water changes twice a week from my since long established 300 gallon DT. QT salinity is 1,024, no detectable NH4 or NO2, temp 75-79 Kelvin, and other values is on par. I use no medications (prazipro is not allowed in my country).

4 weeks ago I introduced 2 long nose hawk fish and a six line in my QT (all from this LFS). Both hawks showed this symptom after 5-7 days and both were eating normally before that. The first died after another week and the second is still hanging on but is getting thinner and thinner since he is not able to catch any food. The six line seems not at all affected.

6 month ago I had the same experience with a Copper Band (also from this LFS)

I have during the same period introduced other fishes from other LFSs without any problems.

I suspect some kind of internal parasite that attack the brain or maybe some kind of poisoning, but have really no know how in the symptoms for this appears. I'm told most of the fish at this LFS is imported from Bali.

Here are a few videos of the fishes showing this strange behavior "“ not particularly great quality, but should show the issue:

http://www.youtube.com/watch?v=WJTpXQrkbQs&feature=player_profilepage
http://www.youtube.com/watch?v=ndXuUF7ZjzU&feature=player_profilepage
http://www.youtube.com/watch?v=pVF_KhE4CHo&feature=player_profilepage

Any ideas ?

 

[anemonekeeper]

It is almost definitely not parasitic. If it was, the fish would have bloating from an immune system reaction. You mentioned a 50% water change twice a week, and that is probably what is killing your new fish. This is because it takes some fish a few weeks to fully acclimate to your tank, and a rapid water change will definitely put a new fish into shock. Symptoms of shock and malnutrition include: decrease of eating habits, loss of fine motion control, thinning, and eventually death. I would try a 20% water change every 1-2 weeks until your new fish are fully acclimated. I hope I helped, good luck.

 

[anemonekeeper]

As for the hawkfish, he is reacting naturally in the video by resting on tge bottom, but he still should have had a faster reaction.

 

[JHemdal]

Magnus,

Well, what I see in the videos are what is termed "moribund" fish - this is a typical reaction to a fish that is close to death. In some cases (when it involves certain parasites such a Uronema) the moribund phase may only last a few minutes. In cases of inanition (lack of food energy) this phase can last days. I suspect that this is what you're seeing. Assuming that not all fish were affected (ruling out external poisoning issues with insecticides, etc.) then in my opinion, I would begin by going back to the source country of the fish. What you saw in the copperband is common enough when fish are collected with sodium cyanide as they do in the Philippines and Indonesia. I don't see that very often in LN hawks, but then I get mine from areas other than those two. If your hawks came from Bali, that could be it. I've done studies that show that the mortality rate of post quarantine fish from these areas is very high, take a look at the chart in this article about midway down: http://www.advancedaquarist.com/2009/12/fish2

And sorry, I just have to add that bloating is NOT a major symptom of immune response in fish and 50% water changes, properly done are not harmful at all. You CAN get emaciation in fish if you expose them to a rapidly changing rise in specific gravity, but I'll assume you didn't move the fish from say, 1.015 to 1.025 at any point. And most certainly, heavy internal parasite loading will cause the fish to become emaciated (not bloated).

Here is a link to an article that I wrote with information about anorexia in fishes: http://www.advancedaquarist.com/2007/12/aafeature1


Jay

 

[magnus]

Jay, thanks for your informative articles... and advice

Both the LN hawk and the copperband did feed normally the first week after introduction into my QT so I would like to assume it was not inanition, but then again - I don't know how it was feeding before that and a few days of feeding may too little and too late. The remaining LN hawk is however still responding to the food but not able to catch it. I will try the feeding stick.

No other fish in the DT show any similar symptoms and neither do the six line in the same QT as the LN hawk.

Speculating on the sodium cyanide poisoning, is this causing permanent damage or is there a chance for the fish to recover ? Is there any way you can see if a fish has been exposed to sodium cyanide ? Does cyanide damage affect the the ability for the fish to digest food even if it feeds and this way still end up with inanitition ?

/ Magnus

 

[JHemdal]

Magnus,

There is no external symptom of cyanide toxicity. The main symptoms of acute toxicity is central nervous system problems. If the fish survive the first few days, the next challenge comes when they feed. The food isn't absorbed properly, resulting in emaciation in some cases, in other cases, the fish just die. Some fish do recover, but the percentage is smaller than people might think. Generally, if the fish makes it for 45 days post importation (so 50 to 60 days post-collection), they would be considered to have "recovered".

Jay

 

[magnus]

Thanks again Jay !

/Magnus