Glass surfing or normal cory behavior?

[PygmyPepperJulli]

Hi,

I have read some conflicting info on the web so just wanted to clarify it with some of the experts here

One of my cories (julii) have been on and off 'glass surfing' since I got it about a month and a half ago. It doesn't seem stressed or sick or anything, and I have read that this is normal cory behavior. My other cories (pygmies) don't seem to do it, and although the peppers do it, it is not as frequently. The false julii doesn't do it constantly, but occasionally just go up, lingers at the top for a bit, and back down the glass once or twice, and then go back to snuffling around in the substrate or plants (it isn't not going for air or gasping anything, just going up and back down again when they reach the top).

I have a couple of ideas of why, but just want to check they might be right-

1. It's just playing. This seems to be the most likely solution, as many sources I read said cories were a bit weird and that this behavior, if it isn't constant, was normal.
2. It's lonely. I have 1 false julii, 2 pygmies and 3 peppers (I know this is bad and wrong, and I am trying to fix it), however they all seem to shoal together or are fine doing their own thing, so this doesn't seem as likely.
3. It's stressed. I would say this is fine (I don't mean 'fine', I just mean understandable) if it was just introduced, however as it have been in the tank this long I would say it would have something to do with the water parameters (nitrate, nitrite, ammonia, ph etc.) , which I think is unlikely because I do large water changes each week and it doesn't have any other symptoms of illness.

Thanks in advance!

 

[GaryE]

I would expect you'd see different behaviour if it were in a group, but maybe not. Corys alone are for looking at. For watching, big groups are needed. Then you see what they do.

I'm inclined to say there's an element of boredom - the zoo lion pacing in its cage effect. So it is stressed, but bored stressed. Fear would have it hiding. Or, it could be a hyper individual. The ways of lone shoalers are mysterious.

 

[Ichthys]

Agree with Gary. Stress... wanting out to go and find others of it’s kind. All of your Corys are stressed in those numbers. I would increase them ASAP, partly because these numbers are unethical and partly because stress invites disease. If you’ve no room for more, change them so that they’re all the same species.

 

[PygmyPepperJulli]

Thanks for that quick replies!

It does make sense that it is bored, especially as you said because it is lacking a group. I try and entertain my fish as much I can (turn the filter on high for an couple of hours a few times a week, they all like playing in the current), but I can't walk them or play with them like a dog unfortunately. Are there any ways you could think of to entertain it? (Other than get him some friends, which is a to-do)

Thankfully, the cories all seem to shoal together or at least hang around each other a bit, but I agree that it needs some friends. Problem is, I only have this one tank that's already pretty full. He used to have a friend, but he died of mysterious circumstances that I believe this forum came to the conclusion that it was something along the lines of internal worms from store. This links in with the boredom/loneliness theory- this behavior has definitely become prominent since his friend died, and that the peppers do it a lot less (it's strange that the pygmies don't do it though).

Again, thank you so much! I just wanted to make sure it wasn't an underlying symptom of some deadly disease or something (stress/boredom/loneliness still isn't good, but at least I know the cause and some possible solutions).

(also sorry about the way this message is worded, I'm in a rush)

 

[GaryE]

Pygmies won't because they are world surfers - Corys that have learned to fly through the water column while the others hang on the ground, like humans.

If you can, try to get at least 5 of a species, and even better, 10 or more. Budget and space kick in there.

In a rush? But it's only 6:30 AM (in Canada at least)..,

 

[PygmyPepperJulli]

Well, the reason my stockings a bit messed up is we went in to lfs to get another 3 or 4 pygmies, and someone I was shopping with (who called the shots) decided not to listen to me, and instead 'let's ignore the pygmies and get another two different species' (It may or may not have something to do with a self proclaimed 'cory expert' that worked in the store). Oh well.

I'm desperately hoping for a second tank for Christmas, so maybe space for a shoal for each species won't be an problem for too much longer . Now I just need the budget... if it doesn't work out I guess I'll have to return them or something, which will be hard because I'm really attached to all of them now.

 

[PygmyPepperJulli]

Also, the reason it was rushed is it was about 10 at night when I wrote this and I was meant to be in bed (because last time I checked QLD wasn't a state of Canada )

 

[Byron]

There is a misunderstanding of how numbers affect shoaling fish, like cories. The fish expects a group, this is in their genetic code, and we are not going to change it. When it is lacking, the fish are stressed. Some fish show increased aggression, but this is a bit difficult for cories who are as mild-mannered as almost any fish. But it does cause stress. Glass surfing is one obvious sign. And stress is the root cause of more than 90% of all disease and health issues in aquarium fish. So it really does matter.

Having said that, I have always found that Corydoras accept each other outside their species. I had some 60 wild-caught cories in my 5-foot tank, and because of the availability in stores I sometimes had two or three of a species. With those species that do seem to spend more time together, such as pandas, this was more obvious. But they do tend to live together, but there is absolutely no denying that having say five of a species is certainly preferable.

And this is an internal need for a group of their own. It has nothing to do with "boredom" in any other sense. When they do not see fish of their own, they are affected. This is scientific fact. Stress during the beginning stages is unseen by the aquarist. It is only when it continues to the point of becoming acute that we then see obvious signs of it.

 

[PygmyPepperJulli]

Thanks Byron. Am just going to state some stuff/question about your message (if I sound passive aggressive or mad, I don't intend it that way at all and am very grateful for your reply, I just don't know how else to word it).

1. I definitely understand that stress matters, which is why I posted in the first place (to check if it was stress or an underlying issue).
2. I now get that it isn't boredom, and instead is needing school mates. Thanks for that.
3. Are you suggesting that this problem is only going to get worse and possibly lead to diseases due to the buildup of stress?
4. When you say that having had lots of groups of cories and having them all get along well together, do you think that in my instance the cory's stress is being reduced by the others? (I am not saying that this means I will not add more of the species. This is more of a short-term solution question.)
5. Why are the pygmies not doing it too, if it is numbers? I know GaryE said ‘Pygmies won't because they are world surfers - Corys that have learned to fly through the water column while the others hang on the ground, like humans.’, but a. don’t really know what that means and b. does that relate to stress?
6. On a totally unrelated topic, I might only have one pygmy now. The last time I saw both of them was about a week ago, and since then have only seen one at a time… I don’t know if it’s the same one because they literally look the exact same.

Unfortunately it seems I don’t have a lot of choices- hope they will all school together and everything will be fine (not likely, coming from the answers on this thread) watch it slowly die of stress (not really an option), rehome it (or all of them) or ask store for a refund on the new false julii (which they probably won’t give, and I really don’t want to let it go, it’s my favourite fish), or buy another 4 juliis, which will cost me around $100 AUS, plus another 3 pygmies and 2 peppers, which will cost an addition $100, which I can’t at all in any universe afford in enough time for the cory. A bit of a stalemate which can only end in death or parting with fish.

Maybe I’ll just sue the lfs for false advertising of Julii’s instead of false juliis and (possibly intentional) misleading of customers in order to sell a product and use the money to get a new tank and school of cories…. (I am joking, by the way. This is most definitely not an option).

 

[GaryE]

Pygmies are very different - they stay off the bottom and seem to surf everything. They're midwater swimmers that shoal with almost identically marked tetras.

Never let a store employee pick your fish, as you know now.

There is debate about how well Corys form groups with other Corys. I find they do, but at night, they sleep in groups of their own species. I have 3 Cory species in numbers I consider too low, because I bought all the seller had at that time. I notice they feed together, but divide by species when they are relaxing. I never see them together at night.

Either way, I can't get more of each species, as they are oddball ones not commonly around. If your tank is too small, you are in a similar boat. They will be more disease prone, and more easily spooked if they don't have a group. I think they assume the others must have been eaten by something out there, and they can be more nervous. But the great majority of aquarists keep these fish in tiny groups. My longest lived Cory was a solo aeneus who beat 10=12 years. I wish I'd offered him a better 10 years, if I had known then it was a problem. But it isn't going to automatically cause problems. As your resources increase, you have time.

And wow, those fish are expensive there. I know the geography but the site won't let me put emojis to avoid literal reading. Your dollar is lower than ours, but even at that things like trilineatus can be bought here at 6 for $ 40. That is a problem for assembling groups.

 

[Ichthys]

Wow, your fish are expensive. Assuming they come from SE Asia, they should cost less to get to you than to get to Britain.

 

[Lcc86]

Pygmies are very different - they stay off the bottom and seem to surf everything. They're midwater swimmers that shoal with almost identically marked tetras.

Never let a store employee pick your fish, as you know now.

There is debate about how well Corys form groups with other Corys. I find they do, but at night, they sleep in groups of their own species. I have 3 Cory species in numbers I consider too low, because I bought all the seller had at that time. I notice they feed together, but divide by species when they are relaxing. I never see them together at night.

Either way, I can't get more of each species, as they are oddball ones not commonly around. If your tank is too small, you are in a similar boat. They will be more disease prone, and more easily spooked if they don't have a group. I think they assume the others must have been eaten by something out there, and they can be more nervous. But the great majority of aquarists keep these fish in tiny groups. My longest lived Cory was a solo aeneus who beat 10=12 years. I wish I'd offered him a better 10 years, if I had known then it was a problem. But it isn't going to automatically cause problems. As your resources increase, you have time.

And wow, those fish are expensive there. I know the geography but the site won't let me put emojis to avoid literal reading. Your dollar is lower than ours, but even at that things like trilineatus can be bought here at 6 for $ 40. That is a problem for assembling groups.

I think you're in a catch 22, you either keep them and save up to increase numbers - but only if/when you get a bigger tank, or return them and start again with a solitary fish, which I appreciate you don't want to have to do. I think (and it's easy for me to say from afar) if I were in your shoes I would consider returning what you have.

 

[Byron]

3. Are you suggesting that this problem is only going to get worse and possibly lead to diseases due to the buildup of stress?

First, let's be sure of just what we are talking about here. I said that each species will probably be better for having a group of each, but cories do get along as my experience and Gary's indicate. I would certainly not return any of them, provided you have a decent number and I would consider 10-12 or more as decent numbers. Having said that, none of us can talk to the fish to see how they feel, and as I said earlier this can go on for quite a time, slowly weakening the fish, until it is too late. Insufficient numbers is like nitrates here, they slowly weaken the fish. And we all know that stress is at the bottom of disease issues.

4. When you say that having had lots of groups of cories and having them all get along well together, do you think that in my instance the cory's stress is being reduced by the others? (I am not saying that this means I will not add more of the species. This is more of a short-term solution question.)

Yes, without question. Ian Fuller has mentioned on his website that hybridization among certain species is the real problem here, but that is a very different issue. You cannot really have too many cories. If you havee ever seen them in the habitat, they number in the hundreds. This is the same species of course, but with this fish there is no doubt that numbers make a big difference.

5. Why are the pygmies not doing it too, if it is numbers? I know GaryE said ‘Pygmies won't because they are world surfers - Corys that have learned to fly through the water column while the others hang on the ground, like humans.’, but a. don’t really know what that means and b. does that relate to stress?

Pygmies are as much affected as other species, perhaps even more so. You want 10-12 absolute minimum of this species. They also have a real likeness for mixing in with small characins, but this canot be taken as a substitute, it is just their way and it applies much more to the three dwarf species. Here's a photo of seven of my pygmies, these were all fry that hatched out in my tank--they love to be together, even when resting.

 

[Lcc86]

First, let's be sure of just what we are talking about here. I said that each species will probably be better for having a group of each, but cories do get along as my experience and Gary's indicate. I would certainly not return any of them, provided you have a decent number and I would consider 10-12 or more as decent numbers. Having said that, none of us can talk to the fish to see how they feel, and as I said earlier this can go on for quite a time, slowly weakening the fish, until it is too late. Insufficient numbers is like nitrates here, they slowly weaken the fish. And we all know that stress is at the bottom of disease issues.



Yes, without question. Ian Fuller has mentioned on his website that hybridization among certain species is the real problem here, but that is a very different issue. You cannot really have too many cories. If you havee ever seen them in the habitat, they number in the hundreds. This is the same species of course, but with this fish there is no doubt that numbers make a big difference.



Pygmies are as much affected as other species, perhaps even more so. You want 10-12 absolute minimum of this species. They also have a real likeness for mixing in with small characins, but this canot be taken as a substitute, it is just their way and it applies much more to the three dwarf species. Here's a photo of seven of my pygmies, these were all fry that hatched out in my tank--they love to be together, even when resting.

OP's problem is that the tank is too small to add more, I forget how small from other threads but OP has had some issues with overstocking and losses recently.

 

[sharkweek178]

Well, the reason my stockings a bit messed up is we went in to lfs to get another 3 or 4 pygmies, and someone I was shopping with (who called the shots) decided not to listen to me, and instead 'let's ignore the pygmies and get another two different species' (It may or may not have something to do with a self proclaimed 'cory expert' that worked in the store). Oh well.

I'm desperately hoping for a second tank for Christmas, so maybe space for a shoal for each species won't be an problem for too much longer . Now I just need the budget... if it doesn't work out I guess I'll have to return them or something, which will be hard because I'm really attached to all of them now.

Never trust fish store employees.