Aggressive cories

[Fiori]

I posted this in the catfish section but thought I would do it here too.

Are cories aggressive? I have (well - had) 6 new gold shoulder cories and having some severe problems with them. I found one dead yesterday and it did'nt have a dorsal fin. Now today I have found one looking very sick, its tail is a stub and it has fungus growing there. What is going on? I have moved him into a QT but I don't think he' s going to make it. They were all fine when I got them.

Do they attack each other? The only other fish they are with are 5 otos.

Please help!!

 

[tttnjfttt]

For the one missing the its dorsal fin, do you know if the fin was damaged before it died, or if it disapeared from the other fish picking at the dead one's body? Also, have you SEEN any agression? The reason why I am asking this is I'm trying to figure out if it is fin rot/columnaris or if you are seeing true fungus growing on an open wound.

Also, can you please post your ammonia, nitrite, nitrate, and pH? It would also be useful to know how big your tank is.

 

[Fiori]

I only got the fish last Sunday, so I've had them in a 55 Uk gall tank, newly set up with live plants and sand substrate but with filter media from another tank. I did'nt notice any wounds, but they have been quite nervous and hiding away every time I approach the tank. I think they are wild caught.

I am doing daily water changes (10 - 15% in the morning and 20 - 25% at night) to keep on top of the mini cycle the tank is going through, but no matter how much I stay on top of it, my ammonia sits at 1 and my nitrites 0.5. Nitrate 15, pH steady 6.6.

Of all the fish, I though it would be the otos who might show some distress at the less than perfect water, but they are fine. I don't know if it has any relevance, but the 2 cories that have had problems have been the darker coloured out of the six.

 

[tttnjfttt]

This is a tough one, as there are so many possibilities. The way I am looking at it, I see two questions that need to be answered.

The first is what is responsible for the fish's behavior. Is it they are not used to humans, they are stressed from agression, or they are stressed from their water. They are definately stressed from their water, but I can't say how much the other two factors are playing in. One thing you can do is add more hiding places in your tank, so the fish will have somewhere to escape to. This will help ease some stress from everything other than the bad water, which you are working on fixing.


The other mystery is what is behind the missing fins and the cause of the "fungus" on one fin. Possible causes of this are either agression or an illness brought on by the bad water. In general, I haven't heard too much about cories being agressive fish. Infact, usually it is the oposite that they are social fish who tend to school. (This could be totally off base, going by memory here). That being said, I would guess that the stress from the bad water had brought on fin rot in addition to columnaris. Columnaris is often mistaken as fungus, while in reality, it is a bacterial infection. To treat this, you will need an antibiotic medicine. Also, turn the temperature in your tank down, to slow the growth of the bacteria (and also making the ammonia less toxic). Here is a link with some more info for you. http/www.flippersandfins.net/flexibacter.htm

 

[Fiori]

I managed to have a look at the remaining four and I can't see any external signs of disease on them, or of damaged fins - is it worthwhile treating the big tank as well as the QT? I know otos can be a bit sensitive to medications as well and the rest of the fish seem fine at the moment - I am worried about making things worse by medicating when I don't need to. Also it will be constantly being diluted by the water changes. I have put some melafix into the QT tank at the moment - I know cories don't like salt but can you add some for a short period, to help heal the wound on what is left of his tail? Can his tail actually grow back?

The dead fish yesterday had not been dead for long when I found it as it was still in good condition (if you know what I mean- colour good, eyes clear) so the other fish would not have had much chance to nibble at it. There were no other fish near it at the time. I've certainly not noticed any noticeable signs of aggression - like you, I always thought of cories being peaceful shoalers. OMG - if I have columnaris, that is hideous to treat I have stuff for it though.

There are lots of live plants and nooks and crannies with bog wood/stones etc. in the tank, so they have places to hide. I think they are stressed from both the water and the fact that being wild caught fish, they have probably been through a lot to get as far as my tank. Poor fish - I feel they have come so far and now I am slowly killing them off. I think I will get a timer so that the lights will turn off for a while during the day when I'm out and see if that helps settle them a bit - I can't reduce it too much because of the plants. I'm also watching that I don't feed them too much - a little once a day at the moment.

Should I get one of those products that lock away the ammonia as a temporary measure? I've never used them before, but the water changes don't seem to be doing much to help at the moment.

Sorry - I seem to have blabbed on for ages here. Any advice is really appreciated - thanks.

 

[Fiori]

Well, I have come home from work and the sick cory has died. So I have done a 40% water change, after doing a 15% one this morning before I went to work. Believe it or not, my readings are still ammonia 0.5 and nitrite 0.5 - that's 55% water that has been changed today and I still can't get the readings to zero. AAAAARGH!! On the good side my other cories are still alive so far and the otos are all whizzing about and munching away quite happily.

 

[tttnjfttt]

I wouldn't treat the rest of the tank, but just recomend that you keep a very close eye on the rest of the fish for any signs of illness. Keep up wiht the water changes. It isn't going to zero because between water changes, the fish are producing more ammonia, so it will be hard to bring it to zero without a 100% water change, which I don't recomend.

 

[memnon]

sorry to hear about your cories, you will just have to keep doing those water changes and keep a close eye on them

 

[Fiori]

I've got one that's headstanding now

 

[Fiori]

Thanks for the advice and kind comments, everyone. As an update, I have just euthanised the headstander, who ended up gasping on his side on the bottom by early this evening. So thats me down to 3 out of the original six. Fingers crossed!!