[lullafishi]

I bought 12 corydoras habrosus on August 25th and put them into a cycled bare-bottom 10 gallon quarantine tank. They have been eating Kensfish golden pearls, tropical flakes, and sinking catfish sticks. Today I am giving them blanched pea.

The first death was 6 days after acclimating them into QT. No observed symptoms so it was a complete surprise but everyone else seemed healthy. The second death I saw coming over 2-3 days shortly after... it was a juvie that stopped eating, stopped moving, and was breathing heavily. Water tested fine but I did a water change anyway. He died overnight. The third death was an adult that suddenly stopped eating and moving. He only had energy to breathe or move if poked with the net. But this time I observed sunken eyes, a hollow belly, and severe emaciation. I hadn't been as attentive in observing each one, so I regretfully am unsure if the emaciation and hollow belly appeared within a day or two or was a more gradual development.

Now I'm worried that something is going on in the tank. Google searches of the symptoms put the fear of mycobacterium in my mind, but I haven't ruled out internal parasites so I begin a course of flubendazole 10% treatment (per inkmkr's instructions). This time I am sure not to overdose like I did with my tetras, haha.

I just performed a 90% water change and dosed flu for the second time. There is one cory that has started exhibiting the same symptoms: lethargic behavior, not eating, not responding when other fish bump into him, breathing slowly, slightly sunken eyes, hollow belly, starting to show signs of wasting. Yesterday he was eating and two days ago his eyes and belly were NOT sunken/hollow.

What is going on? What else can I try? Everyone else is swimming and eating. Does this sound like mycobacterium or could it still be something else? No other symptoms except those listed (no growths/sores/lesions/bumps).

Ammonia: 0ppm
Nitrites: 0ppm
Nitrates: <10ppm
ph: 8.0
50% water changes every 2-3 days

*I have separate equipment for my QT tank to avoid cross-contamination. I'm also washing my hands after handling this tank as I know mycobacterium can infect people through cuts.

EDIT: It's also possible the dying cory may have a curved spine. There is one other currently healthy cory that has the same body shape, but the others don't have such a hump to their heads. Not sure if this is a deformity or just normal difference in body shape?

Sick cory:

What all but one other cories look like (for body shape reference):

 

[lullafishi]

The sick cory ended up dying an hour after I posted the photos. Poor little guy. :c

I'll be keeping a close eye on the others for any beginning signs of lethargy. I have been seeing unmoving things at the bottom of the tank since dosing flu the second time... they aren't poo and look pale and worm-shaped in nature but they are only about 1/8" long. Could these be dead internal parasites?

Still open to recommendations to prevent losing any others. I have flubendazole and levamisole hcl powder on hand.

 

[mistergreen]

if you don't see a worm, it's probably protozoan parasite

use metronidazole or epson salt
http://www.monsterfishkeepers.com/forums/archive/index.php/t-523470.html
I haven't tried the epson salt route.

 

[marcelojc]

Corys are fish that most often are caught in the wild and end up suffering greatly during transport to reach stores too weak!

 

[susankat]

You need a little sand on the bottom of the tank. With cories and plecos a bare bottom tank can and will cause bacterial infections.

 

[lullafishi]

if you don't see a worm, it's probably protozoan parasite

use metronidazole or epson salt
http://www.monsterfishkeepers.com/forums/archive/index.php/t-523470.html
I haven't tried the epson salt route.

Isn't salt generally a no-no with corys? A protozoan parasite could make sense over the lack of a dead worm, unless worms can really be as short as 1/8". I did some more reading and the flubendazole treatment I did is said to be effective against protozoan parasites, including hexamita. I'm wondering if I should try metronoidazole for good measure or wait a bit to see if anyone else falls ill. I'd just hate to not be proactive since they seem to die within a day or two after showing symptoms.

ETA: I'm reading through the article you linked and it's some encouraging stuff. thanks! I'll have to give it a try one I find assurance it's just as safe for cories.

You need a little sand on the bottom of the tank. With cories and plecos a bare bottom tank can and will cause bacterial infections.

All my reading of quarantine tanks recommended bare bottoms but I hadn't come across any warnings about the hazards of BB for cories during QT. Thanks for bringing it to my attention! If it were short-term I'd think they'd be alright, but these guys have been in there for a month already and will be in there until I'm confident I have whatever's killing them under control. I'll add a thin layer of sand... I'm sure it will reduce their stress, too. Their barbels were in bad shape when I bought them and I've been doing regular water changes every 2-3 days, so I'm starting to see barbel growth, but I'll do anything to help these guys thrive.

 

[Hilde]

if you don't see a worm, it's probably protozoan parasite

I agree that it is a parasite affecting the cory. I think Microbe-Lift Natural Parasitic Treatment would help. Found it is cheapest on Ebay.