request for info: blindness in Chromis Viridis

[Reef Rat]

A couple of months ago, one of my Chromis Viridis (aka: Green Chromis), became blind. Apparently, this is known to occur to these fish, but unfortunately, there is not much in the way of published information regarding the cause.

In my discussions with Bob Fenner (amongst others), the idea that this is caused by a nutritional deficiency seemed to be the most likely culprit. An analysis that I tend to agree with. Unfortunately, my efforts to treat the problem with vitamin & iodine supplements haven't reversed the effects. Perhaps I was simply too late in implementing the cure, or perhaps there might be another undetermined cause.

Luckily, my Chromis seems to still be finding enough to eat, but in the interest of assuring this does not occur again (& hopefully adding some valuable info to our collective knowledge base), I thought I'd post to the TRT community the following request:

If you have any info regarding what may be a mitigating factor in this ailment, please post your observations/thoughts to either this board or to me personally.

[For example: Have you noticed this occuring during or after spawning?...a water change? How often, and what, where you feeding the chromis before this occured? Have you had any success in intiating a cure?...how/what? Is there evidence that the fish can indeed see to some degree?...does it react to light at all?...what kind(have you tried getting a response using a red light?)? Could it be that it's simply a deteriation of it's eyesight?...if so, do you know anyone manufacturing eyeglasses for fish? j/k Etc.]

Thanks again...I look forward to your responses.

Steve

[dark horge]

Hi RR/Steve

Nearly all cases of 'blindness' in marine ornamental fish IME seem to be accompanied by disability across-the-board, neurologically speaking. There is apparent locomotor dysfunction, lateral line disability, etc..

Also such incidents are --again IME-- largely associated with shipping/capture trauma (keep in mind, the long-term symptoms for ammonia burn and cyanide poisoning are so similar).

Certainly, a deficiency in the appropriate amino acids can impact neural function, including vision --I just haven't had the dubious pleasure of observing the symptoms popping up in a long-established fish in captivity. Not in person that is.

[Reef Rat]

Hi Dark Horge,

Thank you for your reply! I really appreciate the feedback. I completely agree with your thoughts on what causes such problems in general. However, in this case, I think I've ruled out most of these possibilities as:

1) This particular fish had been established in it's tank for over a year.

2) Other than suddenly (and I mean suddenly...the proverbial "overnight" if you will), becoming blind, it still appears quite healthy in all other regards as do the other chromis which were part of the same "batch".

3) Indeed, it was healthy enough that it was in the process of spawning with its mate as this occured (thus one of my questions).

4) Additionally, it and it's fellow chromis are the Red Sea variety and, therefore, I tend to rule out the possibility that this is a result of possible cyanide poisoning. I admit, however, that if any of the others suddenly come down with a similar affliction, I'll have to seriously consider that as the root of the problem. Who knows if the LFS really knew whether they originated in the Red Sea or in the Phillipines?...or, if they knew, whether they'd tell me? However, before I jump on my LFS (which I do often enough anyways ), it should be noted that the Red Sea is *much* closer to us than the Phillipines and it seems quite reasonable that indeed this is where they originated.

Again, it almost seems to me that the most likely cause is a nutritional deficiency (your amino acids) as I was also in the process of slowly changing their diet as this occured. The strange thing with that is, since I quickly intervened by returning to my original feeding schedule and I began supplementing that with vitamins and iodine, I would have expected to see some signs of recovery.

Unfortunately, I'm sure that there are so many issues at play here that, at least in this specific case, I'll never know with any certainty. Hopefully, more of the board members can begin to observe their green chromis a little more closely. Perhaps together we'll be able to shed a little more light on this unfortunate affliction.

Regards,
Steve

[OodleyBoodely]

With all due respect, IMO, for the fish to have become blind overnight, I would think it would have to be caused by something other than a dietary deficiency. I'm sure you have already looked for signs of trauma to the fish's eyes, but, some injuries don't always show up on the surface. Perhaps the fish was startled and fled into the rockwork or hit the topglass of the tank. I've had fish kill themselves this way and not show any wounds. A blow to the right place on the skull could cause blindness and possibly not leave any mark on the surface.
Another possibility; perhaps the fish have an internal parasite infesting the eyeballs and optic nerve. I haven't heard of anything like this in sw fish, but, they do exist in fw fish. This could also account for others of the same species, especially those from the same location, exhibiting similar symptoms. Also, if this were the case, nutritional deficiency would definately worsen the condition.
You may be right that this is a dietary problem, it just seems that in that case the blindness would progress slowly.

I'm just offering some ideas for further consideration. If you are planning a study of this problem, please keep us informed. I'd be curious to see what comes of it. Good luck.

[Reef Rat]

Hi OodleyBoodely,

Thanks for your input. I'll definitely have to look into the possibility of internal parasites a little more closely.

Could it have "knocked himself silly" on the rockwork? Certainly a possibility, especially if it was "mad as h*ll" because the water change affected either the spawning ritual or the eggs (if any, i observed none).

Like you, I would have imagined that a dietary deficiency would have progressed more slowly, but I observed no signs of that. Perhaps, in this case, it's a combination of a deterioration of the eyesight which lead it to have a traumatic collision with a rock. Who knows? Again, I think I might never find the true cause for this particular instance.

However, in my searches for an answer, I have found the following info:

-this is known to occur to these fish (obviously with a high enough frequency to be noted)

And that's it. No further info is available other than the anecdotal idea that it stems from a nutritional deficiency. So, obviously, this has occurred often enough that people notice, but not often enough that they seem to notice any pattern to it. No indication that fish from a certain "batch" are more likely to get it. No indication that it's parasitic and that it could spread to affect other conspecifics in the same tank.

Of course, I partly attribute this lack of info to the fact that these fish are simply quite inexpensive. So most probably just say, "oh well" and go buy another $3 chromis instead of wasting any brain power trying to figure out what's going on (like they would if it cost $50).

And thus, this post. Yes, I'm hoping to shed some more light on this problem. Any observations or thoughts are most welcome, and indeed, necessary in order to begin making any plausible/testable theories.

I'll certainly keep the group informed if I manage to make any progress towards understanding the problem.

Regards,
Steve

[OodleyBoodely]

LOL. If your fish should die or need euthanizing an autopsy might be informative if you or anyone you know has any veterenarian skills there. Just a thought.

[Reef Rat]

ROTFL

Thanks OodleyBoodley! I really needed that! Maybe I should say what the heck, it's only $3, eh? Then again, considering what've I've already spent trying to save it (time and money), maybe an autopsy ain't such a bad idea afterall? Well, *****, now you've really got me thinking about it... Hmmmm...I can already see that tomorrow my little fingers are gonna be flippin' through the yellow pages.

Cheers,
Steve

[OodleyBoodely]

Glad to be able to inspire. Just think, you could write your own "You can do it, too!" on chromis pathology.

[gregt]

I recently had a chromis that developed blindness as well. Within days of putting him into the tank he dropped to the bottom and swam back and forth along the glass. Occassionally, he'd accidentally get a piece of food, but he wouldn't feed actively. I kept him alive for a little over a month before he developed red sores. After treating him for 5 days with various treatments, he finally kicked the bucket.

Just thought I'd share my similar experience.

[Alice]

I kept him alive for a little over a month before he developed red sores.

We've had problems of this exact sort with almost every Chromis we've tried to bring in over the space of the last few months. I have no idea what it is, we haven't brought any in for over a month.

Alice