Poor corys

1077

In the last year, I have lost three of eight julii corydoras. Symptoms begin with barbel erosion and despite moving the fish from smooth gravel to sand the erosion of barbels continues. Fish then become lethargic and over a period of months,they simply expire.
Currently they are in 56 gal tank .Water parameters are pH7.4 ammonia and nitrites zero ,NitrAtes are consistently 10 to 20 ppm with weekly 50 percent water changes . No new fish have been added in last three months to this tank. Temperature is steady 75degrees f. Remaining fish appear healthy and are fed variety of foods from blood worms,shrimp pellets,flake foods,alage wafers,krill,earthworms,pellet foods,and spirulina pellets.
The fish are easily three years old and I am noticing that of the five remaining ,two have barbel erosion beginning.
Did try isolating the the previous fish that expired and treating them with Metronidazole but can't say it was successful. I increased water changes with previous sick fish as well from once weekly to three weekly 20 percent water changes and that also seemed unsuccessful in slowing or helping heal the previous fishes.
Would welcome any thoughts or shared expieriences .

Angel079

That's sad to hear.
From the little I know (w/out first hand exp there!) the matter of barbel erosion has less to do with your kind of substrate then more a bacterial infection. Its been reported to be successfully treated with Maracyn or Maracyn II; there again I have no pers exp I could share with you there.
Another thought that comes to my find as they sift through the gravel's sand its gotta be clean (or as clean as its gonna get in a tank you know what I mean) so giving the area's they're fed at a good gravel vac will help keep it clean.

Byron

Over some 15 or more years I have had the same experience with the odd cory; with 20-30 different Corydoras from several species mixed, it is very random, although I have noted C. sterbai more prone to this.

I also believe it has nothing to do with substrate (unless obviously it is very sharp, I'm thinking here more of regular small aquarium gravel that is not rough) and Dr. David Sands, an authority on Corydoras, wrote the same. Nitrates have been suggested by some, in your case this is not the issue, nor was it in mine with nitrates at 5-10ppm max. As a precaution I do keep the substrate well vacuumed along the open front areas where I feed the bottom fish, as you do too, yet a fish now and then has had this issue.

As our experiences have been near-identical in symptoms, perhaps someone with more insight can offer further information; I also suspect it may be bacterial or similar.

Byron.

1077

Thank You Natalie and Byron,
I too am leaning towards some type of bacterial activity taking place on or in substrate as the corys are only fish seemingly affected. Tank also holds approx twenty five tetras that all appear to be thriving.
I kept the corys over sand substrate of approx one inch ,along with trumpet snails and confess that I only vaccumed the sand perhaps once or twice a month and usually only to remove excess snails.
Would think that between relatively shallow sand bed,trumpet snails, and once a day ,or once every couple days feedings ,that there was little chance of any problems with regards to bacteria or gases(,sulfide) collecting there. Tank has been running for a couple years with no problems with other fishes and only a few of the corys exhibit symptoms but it is clear to me, that I am not doing something right so I am going to place the fish back over gravel substrate (small smooth), and try vaccuming the gravel each week, a different area each week,and place a small powerhead near the surface of substrate to help keep anything from collecting there between water changes. Am also going to set up a tank with reverse flow undergravel filter and fine gravel (will use plastic mesh to keep fine gravel from falling below), and allow the tank to mature (months) and then try placing the remaining corys (if any) into this tank and monitor them. I feel I must allow the tank to mature so that any improvement (if any) ,,will not be contributed directly to new substrate as opposed to well established tank and mature substrate. While this is happening, I will also monitor the remaining catfish I have ,while increasing the frequency of vaccuming and the addition of some current at or near the substrate in the tank that will house them until UG filtered tank is in my view,,well established.
This whole expieriment will I believe ,take considerable time to realize any possible benefits but I am determined to explore different approach with regards to keeping these fish that have always been a favorite.
Byron are you aware of any links or books I might ferret out with regards to Mr. Sands and his observations ?
I shall in the meantime continue to research different bacterial pathogens in aquaria and possible causes along with possible Fluidized Bed filtration should my expieriment with Reverse flow filtration yield less than desired results.
Hell, for all I know ,this may be just as common in the wild as it is in aquariums but I would take more comfort in losing fish if I try to improve the enviornment I am providing or attempting to.
Again ,many thanks.
Lee.

Angel079

Lee you said some are affected others not...Are the affected one's all from one stock/ one store? There's gotta be something in common with the sick fish and since its clearly not your set up I'm trying to see if it could be something related to what happened with the fish before they came to you.

This scenario reminds me a LOT of my 45g Tetra tank; seemingly all is correctly done yet something still goes wrong....

Do you have a spare UGF? I have 2 of these sheets in my closet that came with one of the tanks I once bought (but I didn't use because of the plants) and its on my list to sell anyway (if I ever get it all together, take pic's and list in the classifies here).

1077

Natalie.
It is indeed troubling.All fish are same age and came from same store. Have bought numerous fish from this store without incident.
This is also not the first group of corys that have exhibited this. But I am determined to see If I can't get to the underlying cause if I am able. I am going to lower the temp to 74 degrees or perhaps a bit cooler to see if I can slow down the process .
I am loathe to try medication and believe that many of the meds only help slow the process or stop it from spreading and I am hopeful that the fishes immune system can combat whatever this is with improved conditions ,and I will as last resort move the affected ones to hospital tank and try meds once again.
I feel moving the two affected ones from the other three at this time ,would only stress the poor devils and I'm gonna try a more natural method If I can.
Thank you for offer with regards to UG filter But I'm thinking of using a rather large tank for my expieriment so that if nothing else is accomplished, I will have a reverse flow filter for possible cichlid tank. Course this means my 75 gal planted tank will have to be put on hold but I am ,,as mentioned,,, determined to see If I can't come to some better understanding as to what may be contributing to this plague it seems.

Angel079

QT any fish is always a difficult decision. Spc when you're dealing with sensitive one's being sick and adding the stress of chasing them around the tank can often make things rather worst then better IMO.

If it indeed is a bacterial matter as often suggested then something must trigger this for some fish in your tank vs others. So I'd also work along the way of improving the immune system with foods for them guys. Also would you think utilizing a UV sterilizer in that case would hep you?
Yea no the things (UGF) I have are for a standard 55g size not 75

1077

Prolly would move the whole lot to quarantine but quarantine tank is curently occupied with recently aquired Von Rio tetras that still have a couple weeks left before I move them to their permanent quarters
As I understand UV sterilizers ,they are good for removing bacterial pathogens from water that passes through the unit but have little effect on that which might be in or on substrate as I suspect this is,considering only the corys who spend the majority of there time there are the ones affected. Is also why UV has little effect on ICH once the cysts fall off of fish and land on substrate.
If I thought it to be a water bourne pathogen, It would be a very good idea . But as tetras don't seem to be affected,I am unclear that UV would be the way forward. One particular group of Bleeding heart tetras has been in the tank with the corys for nearly three years.
Problem does afford me the motive for researching which is something I very much enjoy so long as the subject is important ,or interesting to me. Just wish it were chinese alage eaters that were affected rather than the corys who are /have been,favorites. Chinese alage eaters,,, (wich I despise) I would simply euthanize and not purchase any more.

Angel079

That's what I would do is research, research, research.... Unfortunately there's not too much knowledge out there about fish sicknesses (if compared to humans anyway) and then weed out the good from the bad... Was it my tank I'd research any & all suggestions/ ideas about why this happens to some cory's and not others and then follow the process of elimination in my tank.
After all these years with my tanks and always having had several schools of various cory's I just (luckily) never had that problem so others then offering moral support and/ or articles as I come across them there's little I can offer you to help.
Thou I still am convinced it has to deal with the immune system otherwise there's no explanation why 1 get's it but not the other one being in the very same set up from the very same store, same foods offered etc; if it indeed is a bacterial matter then something had to trigger it for one fish vs another - Finding what makes the difference will be a lot work.

Byron

Lee, another thought occurs to me as I write. I have also noticed this only in newer tanks with recent fish. Right now I have some 40 or more corydoras in the 90g and 115g and not one has any barbel issue. The last I remember was in authumn 2008 with Sterbai after I set up the 90g from scratch (moved it and did a thorough overhaul). Don't know if this is co-incidence or what, just thought I'd mention it.

Dr. Sands' article I came across through a Google search of "David Sands" as I wanted to contact him on a Cory ID. I read the article but didn't save it to my Favs I see.

Byron.