Very Aggressive Cory Behaviour!? Please Read!

[ey2006]

In preparation of adding a group (4-5) of sterbai corys to my old tank, I added 3 of my bronze corys from the small 29g tank to the new 63g tank and immediately noticed something strange. There were already 2 corys in the new tank and as soon as the 3 corys from the old tank were introduced to the new tank, the 3 began chasing the other 2 corys!

Whats weird is that the 3 are actually smaller than the 2 corys, which are already in the new tank. The 3 from the old tank are 3cm wide, whereas the 2 from the new tank are 5cm.

They 3 small corys haven't stopped chasing the other 2 bigger corys since, sometimes they would stop for a break, before starting again! Is this behaviour normal? On the one hand, it looks like they are just playing hide and seek with each other and its all friendly, but sometimes they would chase and bite at each other, this isn't a sign of breeding is it?

I've never seen the 3 small corys do that when they were in the old tank. They would spend most of their time resting on the gravel or would be digging the gravel looking for food.

Any suggestions would be greatly appreciated. I'm not sure if I should move the 3 back to the old tank as a result of this strange behaviour.

 

[dwarfgourami]

Are they all bronze cories?

Are you sure damage is actually ensuing- i.e. that they are actually biting each other? I have never heard of cories doing this; on the other hand, my cories spend a lot of their time chasing each other around and nuzzling at each other, particularly when getting ready to spawn. Do you think you small cories could be males and the large ones females?

Typical spawning behaviour in my peppereds is as follows:

2 males start chasing after the female, falling over her and nuzzling her (and each other); eventually she gets involved too, starts feeling them; they start swimming in front of her blocking her way; the actual act consists in her digging her head into a males side (the T-position) nuzzling him vigorously with her barbels to stimulate him to eject sperm while she lays a small quantity of eggs into a clutch formed by her pelvic fins; she then sets off to find a plant to deposit them on- then they start all over again.

This seems to me like some of the most fun and cuddly sex you get to observe in the animal kingdom. Even when the female is uncooperative (one of mine was slightly offcolour the last time the males got randy and refused to perform), noone ever seems to get hurt.

 

[ey2006]

Are they all bronze cories?

Are you sure damage is actually ensuing- i.e. that they are actually biting each other? I have never heard of cories doing this; on the other hand, my cories spend a lot of their time chasing each other around and nuzzling at each other, particularly when getting ready to spawn. Do you think you small cories could be males and the large ones females?

Typical spawning behaviour in my peppereds is as follows:

2 males start chasing after the female, falling over her and nuzzling her (and each other); eventually she gets involved too, starts feeling them; they start swimming in front of her blocking her way; the actual act consists in her digging her head into a males side (the T-position) nuzzling him vigorously with her barbels to stimulate him to eject sperm while she lays a small quantity of eggs into a clutch formed by her pelvic fins; she then sets off to find a plant to deposit them on- then they start all over again.

This seems to me like some of the most fun and cuddly sex you get to observe in the animal kingdom. Even when the female is uncooperative (one of mine was slightly offcolour the last time the males got randy and refused to perform), noone ever seems to get hurt.

Hi dwarfgourami, thanks for the reply, learnt a few interesting things there!

Yes, all of them are bronze corys, I had 6 in the smaller tank and 2 big ones in the bigger tank and because I'll be getting a group of sterbai's, I thought it would be better to move some from the smaller tank to the bigger one to make space.

There aren't any damage ensuing from the chasing, and their not actually biting each other, they are nuzzling each other (I couldn't think of the word). And you are spot on with the spawning behaviour of your peppereds! They 2 smaller males would chase the big female (I'm only assuming the 2 small ones are males and the big one is the female as I can't tell how to sex them) but they would chase her and nuzzle her, though I still haven't seen her getting involved yet! But once I see the T-position, I think I'll know whats happening )

How long does it take for the eggs to come out? I know this may seem like a silly question, but with human beings, it takes a good 8-9 months for a woman to give birth, how long does it take for fish?? I've never thought about this as I'm quite new to tropical fish and haven't had any of my fish breed just yet.

If they are having sex together, then I'm glad I got to witness it because I keep reading about fish breeding in the forums, but never get the chance to see it! The corys are cute enough as they are, but seeing them cuddle up is really cute. I'm surprised the males got into it immediately as they never showed similar behaviour in the smaller tank (maybe it was all males in that tank?)

 

[AlexAndCarmen]

We've had the pleasure of witnessing our bronze and albino cory's spawn. Normally when you add new cory's they'll have a chase around and can go on for ages, only resting occasionally. They normally calm down after a few days. But if they are ready to breed, they could do this for a few days. Ours normally start the chase a couple days before spawning, and one morning you get up and they are ready to spawn. She'll look around for the perfect place to lay, in bronzes normally the glass. Once she has the sperm from the male, she'll go somewhere quiet, slightly tilt to one side to eject her eggs into her fin basket. Then swim around and lay them. They could do this all day, or only a few times. Normally first time you don't get too many, but once they are seasoned pro's, you could get over 200. They also spawn every 8-10 days, depending on the fish. They do eventually slow down thankfully, otherwise you'd have no where to put all the fry!!! I normally collect them out as soon as they've been layed and put them in my fry tank. The parents do sometimes eat the eggs, so if you do want some fry, you'll have to remove them. Good luck

 

[Barracuda518]

Just because they are chasing each other around doesnt mean they are spawning. Cories are very social, especially the C. Aeneus. They are probably glad to see more of thier own kind. My cories are always chasing and playing around the tank. Sounds like normal behavior to me.

 

[dwarfgourami]

Just because they are chasing each other around doesnt mean they are spawning. Cories are very social, especially the C. Aeneus. They are probably glad to see more of thier own kind. My cories are always chasing and playing around the tank. Sounds like normal behavior to me.

Yes, I didn't mean they are always spawning when they chase each other, more the other way round- that they chase each other even more when they're spawning. But they do love to interact and socialise and touch each other with the barbels as part of their daily bonding.

 

[ey2006]

We've had the pleasure of witnessing our bronze and albino cory's spawn. Normally when you add new cory's they'll have a chase around and can go on for ages, only resting occasionally. They normally calm down after a few days. But if they are ready to breed, they could do this for a few days. Ours normally start the chase a couple days before spawning, and one morning you get up and they are ready to spawn. She'll look around for the perfect place to lay, in bronzes normally the glass. Once she has the sperm from the male, she'll go somewhere quiet, slightly tilt to one side to eject her eggs into her fin basket. Then swim around and lay them. They could do this all day, or only a few times. Normally first time you don't get too many, but once they are seasoned pro's, you could get over 200. They also spawn every 8-10 days, depending on the fish. They do eventually slow down thankfully, otherwise you'd have no where to put all the fry!!! I normally collect them out as soon as they've been layed and put them in my fry tank. The parents do sometimes eat the eggs, so if you do want some fry, you'll have to remove them. Good luck

Hi Alex'sandCarmen'stank, thanks for the advice and info!

I've started another thread regarding the eggs I discovered today, but its in the 'begginer' sub-forum, here is the direct link to my thread:

http/www.fishforums.net/index.php?showtopic=135341

Amazingly, my gut feeling and other ppls opinions were correct! The corys were indeed mating last night! I can't believe it, I only put them in last night and this morning, I had already found over 70 eggs on the glass! When I checked back later in the evening, there were now over 120!

I can't believe they got straight into it, without even having to adjust to the new tank and environment! I was so concerned last night that I even put a sinking wafer (which the corys love) in to distract them, it worked for a while but then they were at it again! lol

If I were to remove all 120+ eggs to a smaller tank, would that mean I could get up to 120+ baby corys? I don't think my tank can handle that! Also, I'm surprised to see that none of the adult corys or other fish eating the eggs!

Would the adult corys or other fish eat the baby corys once they hatch and how long does it usually take for the eggs to hatch? I have a smaller tank, but there are neons, cardinals and juvenile bronze and sterbai corys there, so I'm not sure if the eggs will be any safer than in the current tank.

Is there a good website with guidelines on how to handle the whole breeding process? I'll search around in the meantime. Its so cute and I feel lucky to have witnessed them spawn!