BSJF Necropsy (GRAPHIC)

[thelastmucci]

I really don't have much input as far as what is killing these amazing creatures...I am however glad someone is taking a (semi *read cool*) approach to it all. I hope that you find the answers that your looking for whatever they may be.

[30x30]

I wouldn't infer much about the lack of food in the fish because he was not eating for a very long time. During that time I was able to get him to evacuate once by doing a freshwater dip, to me this explains the lack of material further down the GI. I also know it was not taking any food in for a very long time.

I think the changes in DO2 thickened his GI mucus and trapped sand, this traveled down to a point where it eventually settled to create an obstruction. This fish remained interested in food for 7 or 8 days but the best he could do was swollow the Formula 1, and spit it back out 20 seconds later. I don't know anything about fish physiology, but I wonder if the sight of a meal, or the act of feeding should cause GI-motility, and the lack of this or impairment may have the ability to cause retrograde motility that caused him to spit things out. I do think the grain size was a secondary cause, perhaps larger grains would not be prone to entrapment. That's my final take, I documented a lot of this as it happened in a tread on the BS board.

[vdituri]

Karma to you Scott for taking the initiative on this!

Hopefully we can keep this going to further this study.

Are their digestive systems that much different than say a sand sifting goby (or even other species of jawfish) that a sand blockage in the intestine would be a bigger factor? Or possibly that since there are such a supply of gobies available when one dies we just go to the lfs and get a new one and they may be dying of the same problems with no one noticing?

[thelastmucci]

I like this BSJF allot...but after reading all these horror stories about keeping them in captivity I think their best left in the ocean...if I want a goby that bad I"ll talk to becky..she's queen of the gobies...again job well done scott.

[Dentoid]

Originally Posted by Anselth

Terry, I'm inclined to think it's not a blockage that's killing the fish for a simple reason: The gut is empty. While a blockage in the intestine would certainly prevent the absorbtion of food, you should see undigested matter in the stomach, an overabundance of which would explain the lack of appetite. That doesn't seem to be the case here. I'm kicking around two possibilities in my head:

First, that the sand particles don't block the intestines, per se, but irritate them to the point that the fish does not want to eat. Similar to a human with a stomach bug. Unfortunately, the body is unable to pass the particle and the fish wastes away. I think this is unlikely, however, given that ingesting sand is probably something these animals do in the wild on a regular basis.

Second, a reaction between the stomach acids and the sand is either damaging the stomach lining and intestines, or irritating it to the point that the fish loses its appetite. The fish was apparently living in an aragonite sand bed in captivity. From the limited information I was able to find on the geology of the region, it seems like the sea floor in the Sea of Cortez would be mostly made up of silica and volcanic sands. Remember, aragonite is made of CaCO3, so a strong interaction with stomach acids is possible. The part of this theory that gives me pause is that the yellow-headed jawfish is a Caribbean species which we don't see this issue in. however, the Caribbean jawfishes may have evolved to deal with the interaction of acid and base in their stomachs.

Adam, in this case the stomach was full anterior to the blockage. This picture is of the stomach contents. The mass in the center of this picture are the stomach contents, mainly amorphous microscopically (mucus).



The intestine posterior to the blockage was empty.

These are nevertheless thought provoking ideas.

Cory, interesting observations. We don't know what came first the mucus or the sand. I think the irritation by sand particles that Adam spoke of is a possibility. On the other hand perhaps something else caused the mucus and the sand was secondary as you suggest.

Victor, I believe that most fish have a similar digestive track anatomically and are relatively simple from a gross anatomic perspective. However, in herbivores their intestinal track is longer and more convoluted to accommodate a longer digestive period for the breakdown and absorption of plant material than carnivorous fishes. The BSJF has a short and straight intestinal track which is indicative of their zooplankton feeding preference.

Mucci, I understand your indifference, but there are reports of long term success with this species as long as their specialized husbandry needs are met. They are certainly not a species for the beginning aquarist. BTW, this is not a goby! Thanks for your input.

[Anselth]

My fault Scott, misread the photos!

[Dentoid]

No need to apologize! I could have described the photos better. Keep your ideas coming!

[tbittner]

That's an interesting question. Which came first, the mucus or the sand. The mucus could have certainly trapped the sand from leaving the body. But what could have caused the mucus build up? That possible worm?

[Dentoid]

Good question Terry! I wish I knew. We need a fish gastroenterologist!

[thelastmucci]

boy I feel stooopid hehe..all good stuff though.

[tbittner]

Why? Everyone is entitled to an opinion, and that's what makes RS so special! Everyone respects that right.

[kathywithbirds]

Originally Posted by tbittner

Why? Everyone is entitled to an opinion, and that's what makes RS so special! Everyone respects that right.

Yup!! I have lots of opinions. Lack of information or forethought never stopped me from spouting them!!!

[Dentoid]

That's what we love about you Kathy!

[Anselth]

I just don't get why sand would be causing the blockage, ingesting sand seems like something they would do on a regular basis in the wild. Scott, do you still have the Fish? Can you measure the particle size? Sounds like a good reason to go diving off Baja - need to get substrate samples for comparison...

[kathywithbirds]

So here's one of my thoughts that lack knowledge on the subject:

how about stress all by itself? I mean irritable stomach, irritable bowel, you know, how many of us have thrown up on test/game/report card day? (For me it was first holy communion, we were all ringed around the altar in front a packed church, I think I hit the girl in front of me...)