Decline of the otos - should I attempt a post-mortem?

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Kilgore

Aquarium Advice Activist
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Feb 13, 2006
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Portland, OR
+++Warning: This post is not for the queasy!+++

Well, I know otos are delicate, but I have recently lost three in a row, over a two month period, to a very strange ailment. The otos in question had very swollen stomachs. With the second one afflicted, I realized he was in his death throes as I was completing a water change. He was swimming erratically, unable to control his movements... and then, I noticed that something was starting to protrude from his anus. It looked red. By the time I could even begin to think of what to do, he had died. What a horrible and painful way to go! I later tried to press a little on his stomach and a lot of white fluid came out. I was thinking cammalanus worms until I saw the fluid - that seems more like an infection; plus, there was only a single red filament, and I thought the worms came out in tiny bunches (based on photos I've seen). This "worm" was larger than tubifex, slightly smaller than a bloodwoorm - bright red.

That was about two weeks ago. Today we lost another one (swollen stomach, no protrusion this time). The three remaining otos do not appear to be affected, and none of the other fish are. Water quality is excellent: ammonia and nitrites 0, nitrates 15 ppm, pH 6.8, hardness 4dGH.

So.... I have been considering attempting a dissection (I have a kit), but would that accomplish anything? Not really sure what I am looking for. I don't have a microscope either, so it would be limited to my observations. The weird thing is that there was a thread going (in this forum, or another?) about an oto with the exact same symptoms that had died. I suggested feeding as an issue, and that is still a possibility, but I am not sure how I would identify a blockage if that were the case, and why three otos would get it, and not the others. :(

If anyone has any suggestions, please let me know.
 
i had a a pleco of some sort die. and i took him out to find a hole below his head but around his stomach and it oozed green stuff outta him. it was sick.
but i would definatly like you to cut that fish open and see stuff.
take lots and lots of pictures.
goodluck.
 
I would stick with camallanus as your cause. You will often find a single worm in smaller fish. It is very possible that the worm cause a secondary infection or simply blocked the GI tract and when you added pressure it blew bast.
I used to have lots of problems with camallanus. I would add the jungle medicated food and they would go away for a while only to return. My pleco has harboring them. I bought the Gel-tek medicated food and added ten drops of it to algae wafers and fed those to him and the worms were gone.
 
Thanks for the advice. I decided not to do the necropsy because I just can't take it. I have the UltraCure so I will try it on the algae wafer like you suggested, but I will likely have to treat the whole tank with levamisole because the otos aren't eating. It is probably too late to save the last one that is still showing symptoms (due to internal damage that has likely already occurred). Hopefully the other two will make it, though.

Any ideas why only the otos are infected? I have neon tetras, albino cories, and a dwarf gourami (recent addition) that show absolutely no signs.

I do think I have guppies that are infected in another tank, and I bought them from the same fish store as some of the otos. I won't be going back there! I don't mix equipment between tanks so I am not really sure how else they could have gotten it. :(
 
Did you get them at the same time/place? They may have carried it for a long time. Also, they spend more time digging at the bottom, so they may come into more contact with the worm larvae that hide in the substrate. Your other fish might have it too. If you can get the levamisole, go for it. My only concern would be that the treatment recommends a 100% water change and otos are sensitive to unestablished conditions.
 
Well, I am sad to report that I have lost two more Otos since I began this report. These two went down fast, and didn't show the symptoms of swollen belly and crazy swimming behavior that the others did. In fact, their stomachs looked rather sunken. I had tried feeding them algae wafers soaked in UltraCure last week, and whether it was too late, or too much for them, I'll never know.

There are two Otos remaining, one of which seems to have the swollen belly that the first casualties had. I am having to face the fact that I will probably lose them all. So far, all of the other fish in the tank are doing very well. I am mystified, because I have had these Otos since February and they seemed fine. The only new addition was the Dwarf Gourami, about three weeks ago. And while he developed a dorsal fin issue (small worn areas) about a week after I brought him home, that has cleared up and he is now the picture of good health.

So sad for the Otos. :(
 
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