Possibly Sick Dojos

[TrebleClef84]

OK, here's the deal. I know I shouldn't have gotten these fish, but I've been looking for some nice looking brown dojos for quite some time now... About five years. My LFS has a good reputation for selling healthy fish, so this is a bit of an anomaly...perhaps something wrong with the supplier?

Anyway, these two dojos loaches are a decent size and weight...about 4 inches long. However, when he went to net them, many of them were lethargic, some were dead. I didn't see anything like ich, but thats the only disease I can recognize, so it's possible it could have been something else. Even then, the ich might not have been in the lesions phase. We caught two of the most lively ones that seemed to be acting normal. I set them up in a 30 gallon quarantine tank with some Dr. Tim's and a couple decorations for the established tank, so they're good bacteria wise. I also added a little stress coat. They are showing no signs of illness yet, but it has only been 12 hours. 

Does anyone know what could possibly be wrong with the loaches that died in the store? (the most common reasons anyway, as i know that I haven't provided much info) What would the best preventative treatment for the loaches I have? What would you guys do?

[starsplitter7]

I would check the water from the store. Ammonia, Nitrite, Nitrate and salt. Many stores salt and it really messes up the loaches.

[starsplitter7]

Were you in Petco by any chance? Locally they proudly salt their freshwater fish(to death). Many of the other stores use salt as a preventative, but many don't remove it over time, so it builds up.

[Diana]

Ditto: The first thing I would think of is the store water is not the same as the supplier, or the breeder or where ever they came from. Too many different water chemistry changes in too short a time.
Especially with no indications of other problems.

External parasites would show up by actually seeing the parasites (Ich, fish lice, anchor worm and so on, though some parasites can hide in the gills)
Internal parasites (enough to kill the fish as seen in the store) would show up as skinny or pot-bellied fish, or worms sticking out of the anus.
Diseases or parasites in the gill tissue is harder to see, but holding the fish still and opening the gill cover can show eroding gills, or wrong-color (pale pink or glaring red instead of the healthy red they should be).
Bacterial diseases (again, enough infection to show up as dead fish) would show some sort of surface tissue erosion, depending on the bacteria. Flavobacteria columnaris (one of the most common) would show up as grey patches. Aeremonas (more common in Koi, but possible in any fish) often shows up as sores on the sides of the fish.
Mycobacteriosis is always a possibility. This disease weakens the fish, then the stress of moving to several new tanks in several days can overwhelm the fish, and they die. There may be no external signs, or there may be any of several: Sores and deeper tissue breakdown, and bent spine are pretty common. Dropsy (either all over, or fluid accumulating in the abdomen) is another common secondary problem. The only way to truly diagnose Mycobacteriosis is to dissect a very recently dead fish.
Any sort of tissue damage from bacteria, parasites or injury can get infected with fungus, so in conjunction with any of the above problems a cottony-fuzzy growth indicates true fungus.

Diseases or parasites that are not yet populous enough to kill the fish may not show any symptoms or signs, but the fish might be infected at a low level. Then the stress of being moved is enough to kill them, but still not showing any reason why.

I would start a UV sterilizer on your quarantine tank in hopes of killing off whatever came in with these fish (if anything).

[TrebleClef84]

No, it wasn't Petco, it was Aquarium Adventures. I'd be surprised if they salt their fish...like I said, I've gotten several loaches from them over the years, and they have always been healthy and lively. I actually just got some beautiful sewellia from them a few weeks ago and they are thriving.
However, all the dojos in the store tank (maybe about 20) are dead now. You would think if it were water parameters, a COUPLE of them would have survived at least. I might, MIGHT be seeing some whitish patches around the dorsal area. It sounds a little like columnaris (I read that it's the saddle disease), but maybe it could be a strange presentation of ich? They aren't eating much. I can't really tell if they're lethargic or not because they seem to just lie around like my healthy loaches, but if I poke them, they swim around like normal and seem to have decent coordination.
Another factor that might mean that its columnaris: I don't have an extra heater for the hospital tank, so it is colder in there...about 55 degrees (I usually like to keep them around 65-70). Could that cold temp have slowed down whatever is wrong with them enough to make them live longer than their store friends? Am I just a hypochondriac, and it was actually water parameters all along? I'm treating them with maracyn now just in case.

[DainBramage1991]

I've recently spoken to the owner of my LFS, who runs a fine shop filled with all kinds of healthy fish. She said that in the last couple of years, the Dojos have been coming from the supplier in very poor condition. Consequently, she stopped carrying them, except when people special order them.

I don't know if this is a worldwide problem or local to this part of the US (or maybe just one supplier in particular), but it seems like one possible explanation for the batch of sick fish in the dealer's tank.