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Maybe I'm going to shatter some illusions here.

Yesterday, one of my Corydoras septentrionalis died. It croaked from a combination of stress and the injuries it recieved from other fish. The fish? My other longnose cories, the three largest adults. They shredded all the fins of the victim except for the pectorals, and managed to rip its barbels off (this all while it was alive, by the way). I did happen to see the aggression from the other cories a couple of times, so I know for sure it was them. Ian Fuller confirmed this by informing me that all "long saddle" and "hook snouted" species could become aggressive during the breeding season. Guess he's right- the aggression took the form of one fish swimming up alongside its victim, then slashing it violently with the closest pectoral fin. Ouchies.

Now I'm down to four of these guys, since the one with the lump (see here) died last month, presumably from the lump itself. So just take heed folks, that longnosed cory species can definitely be mean. Some of the longnosed fish are becoming popular (Corydoras narcissus is one), so folks are getting more and more access to them. Any one interested in a longnosed species should be aware that the catfish can kill. From what I've seen so far, all aggression is directed towards fish of the same species. I can't be positive about that though, so don't assume anything.

EDIT: Wheeee, one year anniversary.

Last edited by sirbooks at 26-Jul-2005 10:30

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And when he gets to Heaven, to Saint Peter he will tell: "One more Marine reporting, Sir! I've served my time in Hell."

Congratulations for your 1 year member at FP.

Thanks for the information about the Longnose Corydoras. Unfortunatly these things happen & it's really sad to lose a fish like that.


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. . . wow. That's some news that might be changing some opinions.
Yikes. I'm sorry for your loss.

I'm not surprised... I have heard from several sources that the longnose corys can be aggressive (which is why I choose not to keep them). Though the fact that they actually killed the other one is odd - usually that behavior is confined solely to the Scleromystax species.

I personally have seen marked aggression between my Elegans-type corys (not sure which species). I notice the bigger ones chasing and attacking the smallers ones around the tank until the small one finds a place to hide. The larger ones also claim territories and will chase the smaller ones out.

I have not seen any aggression between the different species though... They only seem to show it to their conspecifics.

Nick, pretty much the only thing you can do to prevent this from happening again is to add more hiding places in your tank so that if one of them is being harassed, it can quickly get away and hide somewhere.

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I'm not your neighbor, you Bakersfield trash.

OH Nick:#(You did ruin my thoughts on my sweet loving corries:#(but then agian i don't have the long nose variety...now i know i won't get any of them, though I don't think I've found any I really like with the long noses...either way, thanks for the information

Oh and Happy 1st Bday

hml

"I've got a great ambition to die of exhaustion rather than boredom." Thomas Carlyle

That's the thing though- I've got tons of hiding spots. There are two mostly enclosed caves and two open shelters, as well as numerous clumps of plants that my catfish all use. It isn't like the fish don't have anywhere to go. Also, the violence I witnessed didn't involve chasing, it was more like a mugging. One example: The muggee left its spot on the gravel to go swim towards the rear of the tank. It was about two inches up off the substrate (it had to clear some plants) when my big female quickly moved alongside, pressed itself against the victim and ripped it. The whole scene was over in two seconds- the poor fish didn't know what hit it. Really unexpected. I know that S. barbatus cats can be brutal, but I figured that Corydoras weren't capable of much real damage.

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And when he gets to Heaven, to Saint Peter he will tell: "One more Marine reporting, Sir! I've served my time in Hell."

Wow, thats amazing. I am really sorry to hear that.

"I am a believer in punctuality, though it makes me very lonely" EV Lucas

Wow! Im gonna have to watch my emeralds more closely, as they are mixed in with smaller, short nosed cories....

Havent had any problems as of yet, hopefully i wont.

Sorry for your loss.

Once again, this proves the point I keep hammering in numerous posts of mine.

WATCH YOUR FISH. CLOSELY.

Because you'll probably alight upon an aspect of their behaviour that is completely missing from the textbooks. Pick up any fish textbook that covers Corydoras catfishes, and chances are it'll describe them all as sociable, peaceful fishes that never run amok or cause any damage to any other fishes. Now my Pandas may fit into this category admirably (and add to the mix their limitless range of comedy slapstick antics) but there are something like 200 different species of Corydoras, and the Genus has diversified considerably throughout South America into a wide range of habitats. So it should come as no surprise that they've diversified theur behaviour also.

Sirbooks has just alighted upon something that is absent from the textbooks. Because he takes time watching his fishes. An object lesson for us all there.


Panda Catfish fan and keeper/breeder since Christmas 2002

Actually, Herbert Axelrod's Atlas of Catfishes mentions that corys do indeed have the potential to be aggressive. He hypothesizes that this is because in the wild, corys are generally found in densities of no more than one fish per square meter in the riverbed, and generally only associate with each other when they are breeding or something frightens them. When we cram large amounts of them into such small places as our tanks, it must sort of stress them out.

I have long thought that when corys form large schools in the tank and go up and down the sides, seemingly "playing", they are actually looking for a way to get out of the tank.

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I'm not your neighbor, you Bakersfield trash.