What Is This Mysterious Skin Disease?

  1. jonesb Initiate Member

    I have a cory cat that has been healthy since I got him over 2 years ago. However, a couple of months ago I noticed a white 'dot' on his head, about the same size as one of his eyes. This has gradually grown to about 4x the size of his eyes, and it appears the skin is simply deteriorating away (the attached pics were taken today). The little guy has so far shown no signs of distress, and continues to eat and explore as usual.

    I have searched images and threads all over the internet but so far have seen nothing that looks like this. My water is healthy, I do regular water changes & gravel cleaning (usually twice a month, but I've done cleanings twice a week since discovering this issue). I have 18 fish in a 45g tank, and all of the other fish are doing great with no visible signs of disease or distress.

    So far I have done no medications (the last thing I want to do is medicate for the wrong disease and end up stressing out or killing other fish), but I would love to know what this is and how to effectively treat it. Has anyone seen this before? Does anyone know what it is? Any help would be most appreciated!

    Attached Files:

  2. KimberlyG Fishlore VIP Member

    Welcome to Fishlore!
    Sorry that you have come because of a problem.

  3. Jayd976 Well Known Member Member

    looks like HITH Hole In The Head (Lateral Line Disease). If that's the case its usually attributed to poor water quality. Check your params and let us know.
  4. KimberlyG Fishlore VIP Member

    (Posted too soon. Sorry)
    I can't believe this is two months old. It has to be due to your fish husbandry skills.
    We can rule out columnaris because of the amount of time this has been going on. It looks to be a secondary infection from an injury. That could either be fungal or bacterial. The only treatment I know that has components for both is Jungle Fungus Clear tabs. It has nutrofurazone and furazolidone for bacterial infections plus potassium dichromate for fungal infections.

  5. jonesb Initiate Member

    Thanks for the quick response. Are you surprised it's two months old because you think it looks more recent, or from further in the past? In 25 years of fish-keeping, I've never seen anything like this, and my fish typically are very healthy and last many years. You mention it could be a secondary infection from an injury. The oldest (and most aggressive) tankmate is a 10-year old YoYo loach, who likes to chase the cories during feeding time. Could a loach have caused an injury like this? Remember, it started out as a small white circle, about the size of the cory's eye.

    I notice the Jungle Fungus Clear tabs advertise that it "protects against secondary infections." To me this sounds like a preventative remedy. Do you know if it will CURE a secondary infection that has already happened?
  6. KimberlyG Fishlore VIP Member

    I would have expected the wound to be far worse if untreated for 2 months. Clean water has helped it from progressing to the almost untreatable things we are used to seeing.
    Yes, he could have gotten injured in a tussle with the YoYo, or he could have been trying to get something wedged somewhere and a piece of gravel cause the problem.
    Jungle Fungus Clear is certainly not a preventative medicine. One of the components, nutrafurazone is the standard "Go To" for bacterial infections because it treats gram negative and some gram positive bacteria. It is also one of the medications that for some reason, bacteria have not found a way to become immune to as apposed to some where the bacteria has become resistant due to not carrying through with the full treatment, treating fish unnecessarily too often, etc. The fungal component, potassium dichromate is toxic to fish. It is administered in a dose that is toxic to fungus, but not to fish in these tablets. Correct dosing is very important. You said you had a 45 gallon...I would dose for a fourty.
  7. jonesb Initiate Member

    Thank you for taking the time to help me. Yes, it has been a very gradual worsening of his condition, and I imagine you are correct that the clean water has kept this from deteriorating much faster. I will try the Jungle Fungus Clear and report the results back here. Of course I will be very careful with dosage and all instructions, but are there any dangers/risks I should be aware of before plopping the tablets in my tank?

  8. KimberlyG Fishlore VIP Member

    Any snails? I would have to research the potassium dichromate in that case. Snails are more closely related to parasites than they are to fish. I'm thinking it is okay because it is a fungal treatment, but I better check. Off I go.

    Can't use the Jungle Fungus Clear with snails. If you have any snails or shrimp, could you move them somewhere else during treatment?
  9. jonesb Initiate Member

    Thanks for this information. Fortunately, no snails and no shrimp. I went ahead and removed my carbon filter and administered the dose for 40g a few minutes ago. The box says I can do a second dose after 4 days if necessary, so I will keep a close eye on it. I plan to do a second dose only if there is no visible improvement - do you think this is a good approach? Also, do you think this 'injury' can completely heal up and look normal again, or has it progressed to a point where the skin cannot grow back and I'm simply trying to stop it from getting worse?
  10. KimberlyG Fishlore VIP Member

    That is a good plan. I see no reason why the effected area would not heal up. Fish are really good at that. (I will say that lateral line will show a pit after healing. I don't think you have to worry about that.)
  11. DoubleDutch Fishlore Legend Member

    What is their diet @jonesb ?
    They look quite thin and in fact underfed what make them vunerable for all kind of infection.

    To be honest the substrate could be part of the problem causee food will get out for reach quite fast (and they will stick their nose in to try to get it : damaging their nose probably).

  12. KimberlyG Fishlore VIP Member

    Was just checking in but I see Dutch has been here.
    I'll be backing out now. Double Dutch is the expert on all things corydoras. You should check out his tanks after your guy is healed.
    Good luck. You are in good hands.
  13. jonesb Initiate Member

    I appreciate your attempts at helping, but unfortunately this mystery was not solved. The Jungle Fungus Clear probably wasn't a good idea in hindsight. A few hours after medicating, the affected area on his head started showing red streaks inside of the white crater, kind of like it was bloody. At first I was hopeful that this was part of the healing process, but after a few days it did not look any better.

    Because there was no improvement, I did a second dose after a 25% water change on day 4 (exactly per the instructions), but the little guy expired on day 5 (today). I suppose the good news is that he appeared happy all the way to the end (ate his usual diet of freeze dried shrimp pellets, flakes, and bloodworms last night, and was actively exploring with his buddy after that).

    If anyone is reading this and has a similar issue, please don't rush out and follow someone else's advice unless they know for certain what the problem is. My guess is this was simply an incurable, perhaps rare, condition that inevitably took its toll. Thankfully it was not contagious, as none of my other fish are having any issues -- knock on wood!
  14. Jayd976 Well Known Member Member

    I still think it was HITH.
  15. DoubleDutch Fishlore Legend Member

    Could you please answer my questions @jonesb.

    Only these answers could lead to the cause of disease.

    Lots (most) disease are caused by keeping (feeding) issues. As said these Corys look very skinny that could mean a diet or substrate issue.