I'm curious if others have experienced aggression with their C. gossei. I had four males in a planted 10 gallon tank (yes, I know that's small for them). The other occupants are two Amano shrimp and two small killifish, neither of whom interact with the cories. One of gossei kept turning up with injuries, and would sometimes rest in the plants above ground level. I kept suspecting problems with the substrate, but I finally discovered the largest male had been biting him!
The poor fish had injuries that looked like he'd bashed into the rootwood in the aquarium (damaged scales), as well as abrasions, lower part of the tail being missing, and even an eye injury. He'd had varying levels of this before, but I assumed he was being stressed for some reason and bashing into things (although I'd never observed it, nor was I able to determine the stressor).
The cories have always appeared mellow when I've watched them, but when I finally saw the attack, the larger male was biting the front of the smaller male's dorsal fin, then scraping off the top layer of the poor fish's scales and skin on his head and sides! The poor little guy didn't struggle very much, which makes me think he was trying to be submissive - or was just exhausted.
Once I observed this behavior, I took out the poor lowest-ranking male out immediately and moved him to another tank (he's recovering okay). Now about four days later, the next smallest male is also showing some similar scale damage, so I plan to move him out to join the first abused male in another tank.
So, two questions: First, if (a huge if) I can find some female gossei, is their presence likely to reduce male-male aggression, exacerbate it, or be unrelated to its incidence?
Secondly, I've never seen cories be aggressive before. Is not struggling a sign of submission? The new omega male seems to lie still, too, when the larger male gets above him and slowly and deliberately bites his dorsal fin. I'm guessing yes, but I find it very wierd. All of the other aggressive fish I've seen (cichlids, etc.) will A) try to chase and/or tear the heck out of the other fish, and B) the victim tries to get the heck out of there.
If anyone else has observed aggression in gossei or in other cories, I'd be curious to know what you've seen.
And no need to suggest a larger tank - I'll be working on addressing that!
Thank you,
Kirsten
C. gossei intra-species aggression
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klingham
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Hi klingham
I've kept some C. gossei for over a year and have never seen anything that would be even remotely considered aggressive behavior toward their own species or any of the other species in their cory community tank.
But, since nobody else has replied to your distressing post, let me suggest a possible explanation and perhaps someone will either confirm it or rule it out.
Could it be possible that your weaker corys have a bacterial infection and the more healthy ones are eating the deteriorating tissue from it? Perhaps if you gave some information about your water parameters, temperature and cleaning practices, it might be helpful. What was the problem you suspected with your substrate?
I wouldn't suggest adding any more fish to this tank until this is sorted out.
I've kept some C. gossei for over a year and have never seen anything that would be even remotely considered aggressive behavior toward their own species or any of the other species in their cory community tank.
But, since nobody else has replied to your distressing post, let me suggest a possible explanation and perhaps someone will either confirm it or rule it out.
Could it be possible that your weaker corys have a bacterial infection and the more healthy ones are eating the deteriorating tissue from it? Perhaps if you gave some information about your water parameters, temperature and cleaning practices, it might be helpful. What was the problem you suspected with your substrate?
I wouldn't suggest adding any more fish to this tank until this is sorted out.
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klingham
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Body slam observed now too
I appreciate your suggestion. I hadn't thought of the possibility of a bacterial infection that another cory might be grooming away. However, as the cory I took out is improving fairly quickly in another tank with similar water parameters, I suspect the larger gossei rather than the anything else.
On the other hand, being a bottom-ranked fish (if that's the case), could introduce enough stress to make that fish be more susceptible to illness, and grooming might play some sort of role at that point. The two big males haven't shown the slightest indication of problems, and the third, slightly smaller, male showed nothing until I took the other one out, but since that time, I've seen the largest male bite that third cory once.
I haven't taken that third one out yet as he seemed to have been okay the past couple of days, but I just now saw one of the larger males come up to him, stretch out all his fins (the smaller one did the same), lean toward the smaller fish, then after about 30 seconds, body slam him a couple of times. The little guy just moved off to a different area of the tank, and all seems calm again. This aggression is certainly mild compared to all other aggressive fish I've seen, but it would be nice if they'd cease and desist. I think I will take the third male out tomorrow after all.
The substrate problem I suspected was a type of flatworm that came in with live blackworms I had been feeding the cories. The flatworms are a species of planarian, I believe. They don't seem to bother the fish, but they hang out in the substrate during the day, and primarily come out at night. Then again, they might be bothering the fish at night when the lights are off, or some pathogen may have been introduced at the same time, perhaps a bacterium as you suggest.
My tank parameters follow:
The general water parameters are fairly stable: pH ~7.6, ammonia 0 (or unmeasurable with a standard kit), nitrate 25 ppm, general hardness ~300 ppm, calcium carbonate hardness ~250 ppm, temperature 78-80 fahrenheit (from room temperature plus heat from flourescent bulb during day; no supplemental heat), reverse undergravel filter with 3" gravel and fluorite, and a Millenium 1000 wet/dry filter for added water movement, cleaning, and aeration.
About half of the 10 gallon tank's bottom is open water, while another quarter of the bottom is available to the cories but covered by a couple of pieces of rootwood with a 2"-3" space beneath for hiding. The remainder of the tank contains Najas guadalupensis and java fern, and the back wall of the tank is a cascade of java moss growing attached to a cork wall.
The tank inhabitants are now three adult male C. gossei (two 3" long, one 2 1/2" long), a male Aphysemion exigoideum (beautiful, slim, 2" killifish), a female Rivulus agilae (1 1/2" long), two male Amano shrimp (1 1/2" long), a couple dozen 1/2" pond snails (plus smaller ones, of course), and an unknown number of uninvited planaria. This should be under the permissible animal load for the tank, although the planaria are hard to measure. The water parameters are staying okay, though, so I don't think there are too many from the health standpoint.
The cories currently get fed 2-3 times per day with frozen brine shrimp, frozen bloodworms, Spectrum Community Formula, and Tetra Min Rich Mix tablets. They only get one type of food per feeding, and eat it up quickly. I want to go back to giving them live food, but thanks to my good supplier of blackworms no longer being in business and to having had problems with the other places, I will have to raise live food myself again (now that it's cooler, I'm going to get a whiteworm culture started up).
Although the pH is a bit high for cories, I have C. sterbai in another tank with similar parameters which have bred often, so I think the water parameters are within acceptable margins for cories. I do 35% water changes in the gossei tank weekly or more often, and take out extra plants when the tank gets overgrown (I have happy plants).
Unfortunately I don't have a videocamera I can use to film the cories, but I wish I could share footage of that body-slam and the dorsal fin bites. At least it's nice if this sort of thing is rare!
I appreciate your time.
Kirsten
On the other hand, being a bottom-ranked fish (if that's the case), could introduce enough stress to make that fish be more susceptible to illness, and grooming might play some sort of role at that point. The two big males haven't shown the slightest indication of problems, and the third, slightly smaller, male showed nothing until I took the other one out, but since that time, I've seen the largest male bite that third cory once.
I haven't taken that third one out yet as he seemed to have been okay the past couple of days, but I just now saw one of the larger males come up to him, stretch out all his fins (the smaller one did the same), lean toward the smaller fish, then after about 30 seconds, body slam him a couple of times. The little guy just moved off to a different area of the tank, and all seems calm again. This aggression is certainly mild compared to all other aggressive fish I've seen, but it would be nice if they'd cease and desist. I think I will take the third male out tomorrow after all.
The substrate problem I suspected was a type of flatworm that came in with live blackworms I had been feeding the cories. The flatworms are a species of planarian, I believe. They don't seem to bother the fish, but they hang out in the substrate during the day, and primarily come out at night. Then again, they might be bothering the fish at night when the lights are off, or some pathogen may have been introduced at the same time, perhaps a bacterium as you suggest.
My tank parameters follow:
The general water parameters are fairly stable: pH ~7.6, ammonia 0 (or unmeasurable with a standard kit), nitrate 25 ppm, general hardness ~300 ppm, calcium carbonate hardness ~250 ppm, temperature 78-80 fahrenheit (from room temperature plus heat from flourescent bulb during day; no supplemental heat), reverse undergravel filter with 3" gravel and fluorite, and a Millenium 1000 wet/dry filter for added water movement, cleaning, and aeration.
About half of the 10 gallon tank's bottom is open water, while another quarter of the bottom is available to the cories but covered by a couple of pieces of rootwood with a 2"-3" space beneath for hiding. The remainder of the tank contains Najas guadalupensis and java fern, and the back wall of the tank is a cascade of java moss growing attached to a cork wall.
The tank inhabitants are now three adult male C. gossei (two 3" long, one 2 1/2" long), a male Aphysemion exigoideum (beautiful, slim, 2" killifish), a female Rivulus agilae (1 1/2" long), two male Amano shrimp (1 1/2" long), a couple dozen 1/2" pond snails (plus smaller ones, of course), and an unknown number of uninvited planaria. This should be under the permissible animal load for the tank, although the planaria are hard to measure. The water parameters are staying okay, though, so I don't think there are too many from the health standpoint.
The cories currently get fed 2-3 times per day with frozen brine shrimp, frozen bloodworms, Spectrum Community Formula, and Tetra Min Rich Mix tablets. They only get one type of food per feeding, and eat it up quickly. I want to go back to giving them live food, but thanks to my good supplier of blackworms no longer being in business and to having had problems with the other places, I will have to raise live food myself again (now that it's cooler, I'm going to get a whiteworm culture started up).
Although the pH is a bit high for cories, I have C. sterbai in another tank with similar parameters which have bred often, so I think the water parameters are within acceptable margins for cories. I do 35% water changes in the gossei tank weekly or more often, and take out extra plants when the tank gets overgrown (I have happy plants).
Unfortunately I don't have a videocamera I can use to film the cories, but I wish I could share footage of that body-slam and the dorsal fin bites. At least it's nice if this sort of thing is rare!
I appreciate your time.
Kirsten
Hi klingham,
The reason I thought your corys might have a bacterial infection is because I just replied to a similar post on another forum, but in that instance the corys were being attacked by normally peaceful platys. When their owner separated them and their symptoms were visable, it turned out that I was right.
I keep my gossei and sterbai in the same tank and they do fine under the same conditions. If yours is improving since it's been moved, perhaps there is something wrong with that particular tank that isn't showing up in the parameters. The presence of planaria might indicate that there is some uneaten food getting caught in the plants or under the wood. Bacteria would feed on it too. Frozen bloodworms can cause a lot of trouble if leftovers remain.
Another thing that can weaken a fish is temperature fluctuations, especially fast warm ups, and this can make them prone to bacterial infections. Could the temperature be dropping at night and heating up again when you put the lights on? Still another thing is low oxygen content in the water. Do you use CO2 in your planted tank?
Several days ago one of my sterbai females spawned for the first time since I got her a year or more ago. Chasing her, along with the sterbai males was a male gossei and she seemed to prefer him over her own species. (Needless to say, I let the eggs get eaten.) Even in this situation I would have to say that he might have been fresh, but he was in no way aggressive toward any of the other corys.
The reason I thought your corys might have a bacterial infection is because I just replied to a similar post on another forum, but in that instance the corys were being attacked by normally peaceful platys. When their owner separated them and their symptoms were visable, it turned out that I was right.
I keep my gossei and sterbai in the same tank and they do fine under the same conditions. If yours is improving since it's been moved, perhaps there is something wrong with that particular tank that isn't showing up in the parameters. The presence of planaria might indicate that there is some uneaten food getting caught in the plants or under the wood. Bacteria would feed on it too. Frozen bloodworms can cause a lot of trouble if leftovers remain.
Another thing that can weaken a fish is temperature fluctuations, especially fast warm ups, and this can make them prone to bacterial infections. Could the temperature be dropping at night and heating up again when you put the lights on? Still another thing is low oxygen content in the water. Do you use CO2 in your planted tank?
Several days ago one of my sterbai females spawned for the first time since I got her a year or more ago. Chasing her, along with the sterbai males was a male gossei and she seemed to prefer him over her own species. (Needless to say, I let the eggs get eaten.) Even in this situation I would have to say that he might have been fresh, but he was in no way aggressive toward any of the other corys.
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Coryman
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There are several species of Cory, especially the snouted ones where aggression is common place, especially at breeding time. This can even result in serious damage being inflicted. With other species the aggression is no more that little squabbles and once dominance is achieved the alpha pair usually settles down and start breeding.
Not all species go through the alpha phase, some are pure group spawners and any male and female in a group will mate.
Ian
Not all species go through the alpha phase, some are pure group spawners and any male and female in a group will mate.
Ian
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klingham
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Hi Inchworm,
I don't use CO2 on this tank, and the O2 levels are fine to the best of my knowledge as the water is aerated by my wet/dry filter. The temperature doesn't fluctuate too much in relation to the lights, but I think you're right that there is at least some food about for the planaria. I do vacuum the gravel lightly every so often, but still and all, that may be causing a problem.
How interesting to learn that your lady sterbai preferred her gossei suitor! I'd let the eggs get eaten, too, but it would be interesting to see what the hybrids would look like.
And thank you, Ian, for sharing your experiences with some cories that do get aggressive. It's a first for me, but at least not an isolated case for cories in general, whether or not for gossei. I appreciate the enlightenment.
Kirsten
I don't use CO2 on this tank, and the O2 levels are fine to the best of my knowledge as the water is aerated by my wet/dry filter. The temperature doesn't fluctuate too much in relation to the lights, but I think you're right that there is at least some food about for the planaria. I do vacuum the gravel lightly every so often, but still and all, that may be causing a problem.
How interesting to learn that your lady sterbai preferred her gossei suitor! I'd let the eggs get eaten, too, but it would be interesting to see what the hybrids would look like.
And thank you, Ian, for sharing your experiences with some cories that do get aggressive. It's a first for me, but at least not an isolated case for cories in general, whether or not for gossei. I appreciate the enlightenment.
Kirsten