fish disease from hell

ok, i have something in my 65g tank that i think i finally diagnosed.

in the past, i have had brackish and saltwater native fish that i have kept that have been struck with the fish killer, Pfiesteria piscicida. i was actually able to catch the nasty little dinoflagellate red handed when i took a skin scraping of the sores that were affecting them. i ended up completely destroying the tanks, because it simply wouldn't go away. well, i think i have encountered it again, this time in my freshwater tanks.

back info: I recently acquired some beautiful native fish from a recent NANFA outing and began slowly acclimating them to my tank. i left them in about five gallons of water and slowly changed their water out with water from my 65 gallon display tank until they were in essentially the same water as what was in my tank. i replaced the tank water in the tank with prepared dechlorinated tap water, as i have always done. the first night, sunday night, all seemed well.
the fish seemed healthy, calm, and content. they even ate a little for me. the next morning i woke up and found that a couple fish had small white spots on them. i tested the water params, 0 ppm ammonia, nitrites were less than .5(enough to read a presence, not enough to quantify on the test i have) and my nitrates were up around 15 ppm. i added CO2 at that time as that always help s my plants pull the nitrates out. the temperature was about 76 degrees and pH was about 7.2. later that day i saw some fish starting to twitch and dart quickly around the tank until they slammed into a wall and knock themselves out. one fish swam up the output of a power-head and managed to make it to an impeller. it didn't fare well at all. at least it was quick... i did a 50% water change and added some dechlorinator just in case i may have had residual chlorine. a couple chlorine tests later revealed no chlorine(liquid drop test, not strips). i added aquarium salt and melafix as treatment and raised the temp to about 79 degrees. by Monday evening the fish looked for the most part OK, except for a few tiny spots that i wasn't even sure was caused by a pathogen(i did just recently handle all of them after all) and strange behavior exhibited by a few of my fish(twitching, darting). the next morning a couple fish were dead and the small white spots non the remaining fish had turned into nasty looking bleeding ulcers. the tank already had a several fish in it, one dollar sunfish(who remains unaffected) one blue spotted sunfish, and a small population(about 6) of gambusia halbrooki. the gambusia were affected, as well as the blue-spotted sunfish. several of my new fish(most of the crescent shiners) had ulcers on them. i added a little more salt and another dose of melafix and did a water change. my tap water has about(at least) .25 ppt ammonia in it, so i try to avoid water changes if i can. i then got dressed and went to work this morning.

tonight, when i got home, i had about twelve fish dead in my tank. i removed all the dead fish( did a thorough search) the deaths include all of my crescent shiners that were less than 1.5 inches long(6 or so), all three Roanoke shiners, and a few rosy-face shiners as well as my blue-spotted sunfish. the blue-spotted sunfish went from having a fuzzy white patch on its dorsal fin to the entire upper half of its body being an ulcer. it was alive when i got home but died withing a couple hours after that. since i have been home, nearly every fish has developed ulcers, except for my dollar sunfish.

for treatment i decided to nuke the tank. i know that my new natives prefer a lower pH, but i have NEVER seen a pH change do this to fish. i did little autopsy of my blue-spotted sunfish and was able to determine that its entire digestive tract was riddled with hemorrhagic ulcers and its liver was very swollen and had a lot of hemorrhagic regions as well. a skin swab revealed small round spores under the microscope. i don't have any agar handy so i cant do a culture on it. since the fish was already dead, i decided that it probably wasn't the best specimen to swab, so i took one of my live affected fish and swabbed its affected area. what i saw under the microscope shocked me. there was an amoeba like creature that i have seen before. as i watched, the water on the slide began to evaporate. as it did, the organism shifted forms into a perfectly spherical cyst. i added a little more water to the slide, after it had completely dried, and the cyst came back to life within a few minutes and assumed a different form, complete with flagella. i have seen this before, but never in freshwater.

what i believe i have is pfiesteria piscicida. looking through literature, there have been instances of it killing fish in practically fresh water, and im sure i haven't been helping the situation by adding salt to the tank. i thought i was doing the fish a favor. looks like i was just giving the pathogen a leg up.

i have already nuked my tank. i turned the filter off, added a large bubble wand and left the power head running(it produces riffle0like currents.) i may have gone a little overkill on the fish treatments this time,(erythromycin, ampicillin, and tetracycline as this stuff leaves them wide open for bacterial infections, if it doesnt kill them) but if i am right, the fish are dead anyway, its just a matter of time. the amoeba thing i saw is one of the toxic stages of piscicida, and it WILL kill all of my fish eventually. When it penetrates the slime coat on my dollar sunfish, it will kill it too. i am removing him into tank by himself, since he doesn't appear to be affected yet.

anyway, since i have been typing this, i have had three more fish die and the sores i see have actually gotten larger. and that is even in the ones i have isolated in hospital tanks. this is some nasty stuff.

i may end up destroying all of the fish plants and fish involved and sterilizing everything in the tank with bleach.

if this truly is caused by a rogue form of piscicida, im not taking any chances and im not playing games. i am fascinated by the little dino, but since i understand what it is capable of, it scares me.

Edited by Auban, 30 May 2012 - 12:00 AM.

You poor thing. One time a mysterious disease took out all my fish too. Clean water, healthy tank. Introduced some new fish and the next day one of them had exploded, with no abdomen left and an extremely rapidly decaying carcass. I removed her but it was too late; the rest of my fish succumbed to the same death. I still don't know what it was. I guess the one positive to all this is that at least you had a microscope handy and were able to identify the bugger. Sometimes with death the peace of mind from knowing what caused it is your only consolation. And a quarantine tank for new arrivals.

Edited by EricaWieser, 30 May 2012 - 06:58 AM.

Wow - I wonder where/how you got it originally? I've never heard of Pfeisteria in aquarium fish - just in brackish estuaries and occasionally at fish farms mainly in coastal areas.

I presume you are familiar with Aeromonas and Flexibacter (= Columnaris), two of the more common diseases on wild caught fish that tend to spread and kill quickly, and have ruled those out? If Pfeisteria is a Dinoflagellate, then maybe meds for treating velvet (Piscinoodinium) might help ???. Or maybe its time for a UV sterilizer. Keep us posted.

The fish i kept from that trip all look fine and Russell told me his are all doing well too.

Reoccurrence may be the result of something surviving the last cleanout process. If you are using anything from the last tank or touched anything during the autopsies it might have recontaminated the new tank or something you put into the new tank. This is purely based on a hypothesis but if it is true then coupled with the ability to survive dry conditions, it would be problematic in complete elimination.

Usil

Edited by Usil, 30 May 2012 - 10:29 AM.

Wow - I wonder where/how you got it originally? I've never heard of Pfeisteria in aquarium fish - just in brackish estuaries and occasionally at fish farms mainly in coastal areas.

I presume you are familiar with Aeromonas and Flexibacter (= Columnaris), two of the more common diseases on wild caught fish that tend to spread and kill quickly, and have ruled those out? If Pfeisteria is a Dinoflagellate, then maybe meds for treating velvet (Piscinoodinium) might help ???. Or maybe its time for a UV sterilizer. Keep us posted.

The fish i kept from that trip all look fine and Russell told me his are all doing well too.

that is exactly where i got it first. i used to frequent those areas and have had it wipe out my tank before. it would cause sores to develop rapidly, right after the fish started acting strange and then getting sluggish. what i saw under the microscope yesterday looked like a few of its several forms. i have been fascinated by the thing since i read about Dr Burkholders work with pfiesteria while i was working for the university of florida. the student who told me about it had been actively looking for similar organisms in the St Johns river in florida. i only know of one case where it killed fish in freshwater, it wiped out a tank of bass in water that was at 0 ppt salinity.

maybe this is a second? i don't know. i did a couple more water changes last night and absolutely nuked my tank. im sure aeromonas and flexibactor are present in my tanks, they are almost always present. i used to prepare petri dishes with agar and test almost every body of water i came across, as well as anything else i could find that might be interesting. the deadly diseases that plague our aquariums are present almost everywhere, they just don't normally cause problems in a healthy tank. i have no idea why they suddenly turn into diseases. i even found anthrax at the edge of a pond on the university of floridas dairy research unit. that was the reason i treated with three different types of antibiotics, to prevent anything that might spring up in tank full of sick fish.

so far, i have lost 15 fish not including the gambusia, all yesterday, but the deaths have stopped. i checked my UV sterilizer and found out that the pump on it stopped working, so i am going to have to replace it. after doing massive water changes to remove any toxins in the water, i turned off the filters and dosed heavily with ampicillin, erythromycin, and tetracycline. since my remaining fish were already sick, i also added metronidazole and praziquantel to prevent any parasites from taking over. thinking back on it, that may be what stopped the fish kill, as it would treat for dinoflagellates. i also added two large airstones to increase the oxygen levels. i left the powerhead on for circulation. right now my fish are all swimming around with open red sores on various parts of their bodies, but they seem to be ok. im going to continue the treatment.

i kind of wish i could be more scientific about the treatment of the fish, as it would be wonderful to know exactly WHAT works for treating this disease, but i guess i cant complain about positive results, even if it was from a completely shotgun treatment. an agar preparation would have told me exactly what was growing in there.

im actually surprised that i don't have anymore deaths, as the remaining fish looked pretty bad.

they still look bad, but at least they are alive.

You poor thing. One time a mysterious disease took out all my fish too. Clean water, healthy tank. Introduced some new fish and the next day one of them had exploded, with no abdomen left and an extremely rapidly decaying carcass. I removed her but it was too late; the rest of my fish succumbed to the same death. I still don't know what it was. I guess the one positive to all this is that at least you had a microscope handy and were able to identify the bugger. Sometimes with death the peace of mind from knowing what caused it is your only consolation. And a quarantine tank for new arrivals.

the only thing i know of that does that is tetrahymena.

"the deadly diseases that plague our aquariums are present almost everywhere, they just don't normally cause problems in a healthy tank. i have no idea why they suddenly turn into diseases."

The fish's immune system might become compromised by something else, allowing the normally tolerated organism to become able to cause disease.

Or the organisms could rapidly change their behavior through quorum signaling.

it never fails to surprise me how fast fish can recover. almost as fast as they can can get sick! no more deaths and the bloody ulcers are now discolored skin. in an effort to improve water quality, i added fertilizer tabs under the fastest growing plants and added CO2. plants have been sucking up the ammonia, which is good since i nuked all the beneficial bacteria with antibiotics.

Auban,

Were these crescent shiners from Stinking Quarters Creek? I ask this because, all of my crescents died also. They were fine in the cooler that I brought them home in. I added my treated water with a drip tube and held them in the cooler for two days. I moved my swallowtail shiners from the 15 gal. that I was holding them in for the last three months, did a 50 % water change, and added the crescent shiners, killifish, and darters to the 15. The next day, Wednesday, most of the shiners were dead. Thursday the last two shiners died. I lost 1 darter on Friday and no loses since. I did a water change today so I will see what happens.

I had a previous problem with this tank where I kept losing livebearers, but broke down the tank and bleached everything. I ran the tank empty for about two months before I added the swallowtails and had no problems since.

If both of our shiners were from the same location, I would find that to be curious. Or maybe they are just super sensitive, I don't know.

Harry Knaub

Edited by harryknaub, 03 June 2012 - 07:29 PM.

No, Auban's crescents were from Hyco Creek. Harry could something have gone wrong with your 50% water change, like maybe high temp or low DO? In summer I often have to let the "COLD" tap water cool off in a barrel before using it; it can be mid-80s (and presumably low in oxygen). Did you see any disease-like symptoms, or did they just die with no apparent symptoms, which to me suggests a WQ problem rather than disease.

Gerald,

The water sat overnight before I did the water change. The shiners fins did look a bit ragged when I moved them from the cooler to the tank.
I suppose that the Fundulus rathbuni must be quite hardy since I didn't lose any of the seven I brought back.

Harry Knaub

in my experience, if a fish from a water source that has a disease, it is usually one of the last ones to catch it in a tank. the biggest exception to this is diseases that release toxins into the water. in cases like mine, the fish that have not been exposed to the toxins already start to act a little wierd but take a little longer to die, with the fish that had been exposed longest died quickest(my gambusias and ironcolor shiners) the only fish that i had that died right away were the fish that i added, not the fish already in my tank.

that tells me that my problem was already in my tank, whether it be water quality problems or toxic disease. none of the new fish could tolerate whatever i already had going on.