Tang internal anatomy/dissection (Graphic)

[Cjud7982]

So I have been helping my lfs for quite some time managing and setting up their systems. And it seems that every order we lose what appear to be perfectly healthy fish. All eat, swim well, and generally speaking look great. Then when we show up in the morning many of the fish that looked great are now dead. Now these aren't obscure fish, they're the standard hobbyist fish, yellow tangs, blue tangs, clowns, wrasses, goby's. Your basic stocking fish that I personally have never had any issues keeping.

I was in the store today to do some tank cleaning and maintenance and watched a yellow tang breathing very heavy, and had a muscle spasm and died. This is the third order from this supplier where about 60-75 percent of the fish die within 4-8 days after being acclimated.

I acclimate the fish by temp acclimating, then do one fish at a time by emptying the bag water and fish into a separate container then add system water over the period of about 20 minutes, then transfer the fish to a methylene blue dip with system water for a few minutes, then in the tanks they go.

This technique has never failed, me before. I don't like doing fw dips upon receiving because they are already stressed. I do fw dips as needed.

So after the third order doing this I am starting to look at the supplier. It's like clockwork.

That being said I took the yellow tang home for dissection and to my knowledge didn't see anything out of the ordinary. Gills looks good, nice color, stomach very full, intestines seemed fine, what I believe to be the liver looked normal, but I did see a bright red "blood sac" that was attached to the stomach/liver. Now I am not a marine biologist, so I am not an expert on marine fish anatomy, which is why I am looking for input.

Reason I did this is because these fish show no external parasites, no white stringy poo, great color, good swimming, and then just bam,they die.

We are getting very frustrated with the mortality rate and looking for what the cause is, cyanide,internal parasites, lack of oxygen, anything other than the normal causes of death.

Water param are
Temp 77-80 depending on day temps
Salinity between 1.023-1.024
Ammonia 0
Nitrite 0
Nitrate 80ppm
Alk 8.2-8.5
pH 8.1
Mag 1350ish
Calcium 470

Any help is greatly appreciated. I've attached a photo of the dissected fish once the flesh was removed.

 

[Big G]

I would consider doing a gram stain of the fish's blood. Gram negative bacterial infections can kill rather quickly without warning.

 

[Cjud7982]

Ok, I am willing to try anything at this point. I will have to do some research on gram staining as I am unfamiliar with it. Do you have a source for a procedure?

Also, even a gram negative bacteria infection would show external lessions right? All of these fish show no visible sores, red spots, or anything.

 

[Cjud7982]

Also a side note, some fish do show signs of ich from time to time. This I fully expect in a retail environment and rather than having the pet store attempt to mitigate it, they chose to manage it with healthy feedings with vitamin enriched foods, clean tanks, and minimal fish per tank. We advise all customers to assume every fish has ich and to qt them prior to going I to their display. I have never seen ich be this lethal this fast, I have seen the worst of velvet before, but all those fish that died had very clear visible issues.

 

[Big G]

Ok, I am willing to try anything at this point. I will have to do some research on gram staining as I am unfamiliar with it. Do you have a source for a procedure?

Also, even a gram negative bacteria infection would show external lessions right? All of these fish show no visible sores, red spots, or anything.

Bacterial infections can be internal without any external symptoms. Sometimes caused by poor water conditions (think shipping in a bag, holding tanks with dead fish, etc.), illness, injury, parasites, etc.

Best place to take a blood sample for the gram stain on a tang is the heart.
Gram negative will stain pink/red; gram positive will stain a kinda violet/purple

How to Do a Gram Stain Test | Step-by-Step Guide

Step by step Gram staining guide at Microscope.com. Learn Gram stain basics, reagents, and tips for labs. Fast free shipping and expert support for supplies.

www.microscope.com

 

[Cjud7982]

Thank you so much for the information @Big G . Unfortunately I discarded the remains of the yellow tang. Unfortunately at this point in time I feel it's inevitable for another fish to pass in the near future and will attempt a gram stain on the next fatalitly.

I will research gram negative bacteria infections. I am assuming that once a gram negative bacteria is in the system it is essentially there indeffinity? All the rock, substrate, equipment must be sterilized in order to rid the system of it?

 

[Big G]

Thank you so much for the information @Big G . Unfortunately I discarded the remains of the yellow tang. Unfortunately at this point in time I feel it's inevitable for another fish to pass in the near future and will attempt a gram stain on the next fatalitly.

I will research gram negative bacteria infections. I am assuming that once a gram negative bacteria is in the system it is essentially there indeffinity? All the rock, substrate, equipment must be sterilized in order to rid the system of it?

Lots of opinions on this ^^^ as in our tanks we always have good and bad bacteria floating around being breathed in by our fish. Generally speaking, if a fish's immune system is in good shape, nothing happens. But when the fish's immune system is compromised then the bad bacteria can attack the fish with success. We see lots of this with newly shipped fish. One of the results is for many to dose antibiotics prophylactically on all incoming "shipped" fish. Especially when they will be treated with other meds for parasites which further suppress the already compromised immune system.
So wide spectrum antibiotics like Kanaplex, Furan2, Spectrogram are popular to treat for both active and potential gram positive and gram negative bacterial infections.

 

[fishguy242]

following ,never too old too learn!!

 

[Big G]

Also a side note, some fish do show signs of ich from time to time. This I fully expect in a retail environment and rather than having the pet store attempt to mitigate it, they chose to manage it with healthy feedings with vitamin enriched foods, clean tanks, and minimal fish per tank. We advise all customers to assume every fish has ich and to qt them prior to going I to their display. I have never seen ich be this lethal this fast, I have seen the worst of velvet before, but all those fish that died had very clear visible issues.

Due to some shippers, wholesalers, LFS treating their fish with "sub-therapeutic" levels of copper, we've seen a disturbing number of velvet deaths as the fish's gills were hiding the parasites within the mucous coating. So as soon as the fish are not in the copper, the parasites come roaring back deep within the gills killing the fish without the usual exterior symptoms. Uronema also prefers the gills first, and kills quickly.

 

[Cjud7982]

Due to some shippers, wholesalers, LFS treating their fish with "sub-therapeutic" levels of copper, we've seen a disturbing number of velvet deaths as the fish's gills were hiding the parasites within the mucous coating. So as soon as the fish are not in the copper, the parasites come roaring back deep within the gills killing the fish without the usual exterior symptoms. Uronema also prefers the gills first, and kills quickly.

I have heard and seen many fish stores do this with copper and strictly for bid it at the store I am helping. It is trickery and a shameful scam in my personal opinion. I have not tested the suppliers water for copper, but will be sure to have my Hanna meter there next time a shipment comes in.

I also have not ruled out velvet in the gills yet. However I saw no fill damage on this tang, I guess I am not sure if I visually would have seen the velvet or not on the gills during the "autopsy".

And honestly I've been fortunate with my time in the hobby to never have to deal with uronema. Only experience or knowledge I have of it is from reading. So let's hope that now I don't have to learn about that one first hand!!!

 

[Big G]

I have heard and seen many fish stores do this with copper and strictly for bid it at the store I am helping. It is trickery and a shameful scam in my personal opinion. I have not tested the suppliers water for copper, but will be sure to have my Hanna meter there next time a shipment comes in.

I also have not ruled out velvet in the gills yet. However I saw no fill damage on this tang, I guess I am not sure if I visually would have seen the velvet or not on the gills during the "autopsy".

And honestly I've been fortunate with my time in the hobby to never have to deal with uronema. Only experience or knowledge I have of it is from reading. So let's hope that now I don't have to learn about that one first hand!!!

You need a basic "student level" microscope to closely examine the gill filaments for parasites. Plus you'll be able to distinguish between the various types of parasites which is kinda cool.

 

[Cjud7982]

Ahhh got ya, I didn't know I had to look that close on the gills, I assumed it would have looked like the normal velvet just on the gills. I do have a quality microscope that I used for my tanks at home for identifying algeas and bacterias, so Ill be sure to use that on the gills next time!

 

[reefproaquatics]

Are these fish imported/ transhipped or coming from a US wholesaler? You may want to remove the fish from the bags and add directly to clean temp/salinity matched saltwater, and then acclimate to your system.

 

[Cjud7982]

Are these fish imported/ transhipped or coming from a US wholesaler? You may want to remove the fish from the bags and add directly to clean temp/salinity matched saltwater, and then acclimate to your system.

At this point I am assuming the fish are being transshipped. The owners of the pet store currently use a supplier that I do not know anything about. Unfortunately they are not versed enough in the marine hobby enough to know the difference, which is why they are "consulting" me or allowing me to manage their marine stuff. These are the questions I am asking the owners to get me answers to, and unfortunately they don't even know where the supplier is getting their fish or if they are being held in holding tanks or just being transferred to them. I am currently assisting them with identifying better suppliers with a known reliable methods of handling and holding of fish. All I know is that they are delivered from somewhere in Ohio. I am assuming they are transhipped to JFK, then shipped to the supplier, repackaged and then shipped to the pet store. Which is bad news all around. I told them to either get pictures of their holding facility and a very clear explanation on how they handle their livestock prior to distribution. The next order of livestock will not be through them to determine if it's a supplier issue.

And thank you for your input on acclimating. I may modify my acclimation techniques to help minimize the exposure to the suppliers water.

 

[Cjud7982]

@Big G , are you familiar with the internal anatomy of these fish? I have only dissected a couple in my experience and still struggle some on identifying organs with some fish. This tang seemed a little difficult because everything is so confined together. Can you confirm the dark red triangle shaped organ between the stomach and the esaphagus? When dissecting it, it didn't really have any mass to it. Seems more like a hemmorage or sac of blood. Maybe confusing this with a kidney? Also, just to confirm, the gall bladder is the small very dark blue/green ball attached to the stomach, the liver is the pink flesh mass attached to the stomach towards the head? It seems that the organs are not consistently located and shaped between species, for obvious reasons

 

[Big G]

Without seeing the actual fish, it's a bit hard to say. But you may be looking at the spleen. Or it could be part of the bacterial infection as a possible internal septicemia.

 

[lostcause]

Heres a good step by step on how to gram stain. As with any good microbiology make sure you wear gloves and sanatize your work area before and after.

How to perform a Gram stain

 

[tehmadreefer]

Lol throw that bad boy in the frying pan! Lol

 

[Big G]

Heres a good step by step on how to gram stain. As with any good microbiology make sure you wear gloves and sanatize your work area before and after.

How to perform a Gram stain

+1 ^^^ it's not uncommon for fish to have TB.

 

[NanJ]

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