alison

hey all, i've got a cory whose fins are starting to look sort of ratty. my 10g has been running for about six months now, and i keep my water conditions very good (no ammonia, nitrites/ates, etc, and it's just slightly acidic, around pH 6). i have two cories, and only the one cory seems to have this problem. he's as active as ever and his appetite is fine, but his fins just look sort of torn-up. i have fairly coarse-grained substrate, but it doesn't make sense to me that one cory would have this problem and the other wouldn't if the substrate were the culprit. please help!

__________________
I was born upon thy bank, river,
My blood flows in thy stream,
And thou meanderest forever
At the bottom of my dream.
-H.D. Thoreau

Tommy Gun

Hey alison - welcome to the forum! Sorry to hear about your cory though....I am sure we can help you out.

First, since fin rot can be caused by a couple things, it might be helpful to figure out what is the most likely culprit so you can treat appropriately and then avoid it in the future....

Perhaps the most common problem that tail/fin rot stems from are injuries. Can you tell us what other fish are in the tank with the cory? Have you noticed any of them chasing the cory around or "picking" on it? If you think this might be the problem, it is probably best to fix that situation. In this case, the fin/tail rot is generally a bacterial infection (the injury being its window of opportunity) so you have a couple ways to go there. In my humble opinion, it is better to treat for bacterial infections by removing the fish from your main tank and keeping it in another, usually smaller tank, until it is better. This is because there is some risk that the medicines (antibiotics) will kill off bacteria that you want as well as those you don't want....causing problems later on. It is also somewhat stressful on your fish so it is usually better to keep that stress to a minimum...meaning, only subjecting the sick fish to the meds.

Another common cause of tail/fin rot is poor water quality. I know that you say you have no ammonia, nitrite, or nitrates (although you should have some nitrates), there may be other problems. How often do you perform water changes and when you do, how much water do you change usually?

I know that is seems odd that only one of your fish is sick or showing signs of a problem, but this is probably a sign that it is not as healthy as the rest of your fish. In general, any healthy fish should have a relatively easy time with fighting off bacterial/fungal/parasitic/etc infections - which is why we talk to much about stress on forums like FTF. Point being, figuring out what might be different with this fish (e.g. it is a favorite target of another fish, it is not getting enough food, not getting the right foods, etc....) versus the other, apparently healthy fish is the true key to getting past the problem and most importantly, preventing it. With that being said, any other information you can give us would probably be helpful in your quest to recieve rapid, more accurate replies.

alison

thanks Tommy Gun i've got the two cories, plus two small goldfish and two young mollies. and now that i think of it, the one cory looked a little ragged the day i brought him home, even. i had a pretty aggressive molly, who did attack the cory and one goldfish (about 6 weeks ago, i think) and i took him back to the store in exchange for a smaller female, who's much more peaceful. i do 30-50% water changes about twice a week (such is life when you keep goldfish!), but have been doing them more often because of the cory's declining condition. he seems to have been getting better very slowly since the bully molly left the tank, though. is there anything i can do to help speed the healing process for him? also, another question: i've been using Start Right to treat water before adding it to the tank, but i realized recently that it contains NaCl and KCl, which i've read can be harmful to catfish. should i switch to something else?
thanks so much for your help; he's a tough little guy and i know he'll pull through!

__________________
I was born upon thy bank, river,
My blood flows in thy stream,
And thou meanderest forever
At the bottom of my dream.
-H.D. Thoreau

Tommy Gun

To be honest, the only chemical or product that I add to any of my FW display tanks is a dechlorination conditioner. I happen to live in a silly area of the world where my LFS(es) don't believe in carry the same product all of the time so I often switch between them, but I do try to stay away from those that contain aloe....however that is my personal opinion and I am not really trying to knock those products. As far as the additional salts, I don't think you need them, but I don't think they are the cause of your problem. My somewhat educated opinion is that the idea that catfish and/or scaleless fish cannot handle salt is over stated though. So, my admittedly wishy washy suggestion would be to do what you feel is best as far as what you do or do not add to your tank.

Hopefully I am not insulting your intelligence here, but I was wondering if you keep your tank heated? I believe that mixing tropical and coldwater fish can cause some problems, but perhaps slightly more so when keeping tropical fish at sub-tropical temperatures....which could be another reason for the tail/fin rot. My guess would be that your tank is at the right temp for the cory but I thought I would ask anyways.

The good news is that fins can grow back. Sometimes it takes a bit longer than we would like, but the key indicator would then be that the problem isn't progressing. Many people might suggest using a product such as Melafix or Pimafix....and I have used them myself but with mixed results - in one case, very very bad results....but even the company itself (API) has gone on record recently stating that the antibacterial properties of the "all natural" medicine is sort of hit and miss (my own translation); meaning it may or may not work the same in your tank as it may in mine. I do think that if you can work to keep your fish healthy and/or regain its health, whatever the case may be, it should be able to recover on its own and I wouldn't run to the store shelves until I realized the trend was heading toward the worse......but again, that is just my personal opinion and I am sure others might disagree with me emphatically.

cassb

That's weird because I just had the same problem myself. I had three Corys. One developed finrot on the tail fin only, really quickly. Like 1 day it was 1/2 gone, then next day it was totally gone, just a stub. The other two Cory's are fine. I changed 50% of the water (since this is a relatively new tank -- thought it was water quality maybe) and vacuumed up the gravel as much as I could. The cory died a couple days later, unfortunately. I'm not sure what it was, but the other fish (just Corys and silvertip tetras at the moment) in the tank seem to be fine. I'll chalk it up to maybe a fish that was already sick and just got worse in the new tank. It was only in my tank for 2 weeks.

Tommy Gun

Hey cassb,

Your situation is a good example of when running to a store shelf might be the best thing to do since the problem was progressing so quickly. I would also think that your situation was sort of the extreme. In short, the only reason I said that I might postpone a treatment in alison's case is because it sounds like it already had ragged fins at the store so my guess would be that it is an injury at this point and may not be infected. Honestly, I am basically trying to say that I would be very sure of myself before I started adding antibiotics to a display tank....but if there is a hospital/Q-tank available, that would be a different story.

alison

Thanks again for your advice, Tommy! I keep my tank around 76-77 F. The goldfish are tough, and spent the first weeks of their lives in a drink cooler with 200 other fish, so they're happy enough to have survived that! i think you're right, that since the cory doesn't seem to be getting worse very quickly, i doubt there's a severe bacterial infection. i'll just try to keep the water quality good and see if the tail mends itself (one of his fins has already started growing back, so my hopes are high!) thanks again for your advice; this forum is really a wonderful thing, because it allows fishkeepers to learn from each others' experiences. thank you for your quick and helpful suggestions!

__________________
I was born upon thy bank, river,
My blood flows in thy stream,
And thou meanderest forever
At the bottom of my dream.
-H.D. Thoreau

cassb

Well, I have Furan and some other antibiotics here at home, but I didn't put anything in the tank. My thought is that unless a disease is widespread and affecting several fish, I won't treat it. I don't have a hospital tank set up, so the fish that die, die -- the rest should be OK. I have found that you will inevitably get waves of diseases going through the tank when you're adding new fish regularly. The weak or sick ones will die off, so knowing that, you get a couple extra. Then once the tank is fully stocked, you should have a pretty healthy group, and they should stay that way for months or years if you don't add any more fish and keep tank conditions stable.

Tommy Gun

Well, unless you have a quarantine/hospital tank I guess my logic centers on the fact that if I can prevent problems from running rampant in my tanks, I won't have to add new fish regularly.

Don't get me wrong though....I never said that we should never, ever treat our fish in a display tank. Above and beyond those circumstances where doing so is recomended (e.g. highly contagous problems like Ich), if I didn't have another tank, I would dose meds into my main tank versus watching things get worse. IMHO, the "letting nature take its course" theory is pretty flawed unless we are speaking about fish that are actually living in nature.

cassb

Or if you don't mind paying money for more fish to weed out the weak ones and end up with the strong ones.