Corydora staying in the corner of the tank

[pepper169]

Hey guys a few months ago i got 3 corydoras and they were doing well and swimming around, but recently one out of the 3 has been staying in the back corner of the tank all alone and won’t move. he definitely is alive because i kinda nudged him out of the corner with a net because i was worried myself he was dead lol but he wasn’t. but after that he was out for a few minutes and then went straight back to the corner. the other two are happy and seem like they are growing well they play with each other all day. yet this guy looks like he’s getting smaller. i’m assuming it’s because he’s staying in the corner he’s not eating. my water quality is all good Ph is at 7.0 and i do a 50% water change weekly. i’m just worried he is sick? i’m not sure what’s going on he usually plays with the others until recently.

 

[mrsjoannh13]

Can you tell us more about the tank - tank size and the other water parameters (ammonia, nitrite, nitrate, GH, KH, water temperature)? What other fish or livestock are in the tank? Also, corys like to be in groups of 6 or more. He may feel stressed because there are not enough of his kind.

Could you tell us more about feedings? Do you have fish that feed at the top and are maybe getting all the food before it makes it down to the bottom?

 

[FishGuest5123]

Can we get a pic of the fish also, please?

 

[pepper169]

Can you tell us more about the tank - tank size and the other water parameters (ammonia, nitrite, nitrate, GH, KH, water temperature)? What other fish or livestock are in the tank? Also, corys like to be in groups of 6 or more. He may feel stressed because there are not enough of his kind.

Could you tell us more about feedings? Do you have fish that feed at the top and are maybe getting all the food before it makes it down to the bottom?

the tank size is 10 gallon i know they need to be in bigger groups i only got 3 because that’s all the pet store had at the time and i’m not entirely sure if they are julli or false julli so i didn’t wanna get the wrong kind when i add more. but nitrate and nitrite are both at zero water temperature is at about 75 degrees f GH-180 and KH-80. i know the gh is really high and i’m unsure how to fix it as my water is really hard and no water conditioner seems to lower it without completely covering the tank in white residue. i have no other fish besides the corys. i also feed them sinking shrimp wafers and they seem to love them. i’ll get a picture in a sec here but if you have any advice on how to get the hardness out of the water that would be helpful

 

[pepper169]

the tank size is 10 gallon i know they need to be in bigger groups i only got 3 because that’s all the pet store had at the time and i’m not entirely sure if they are julli or false julli so i didn’t wanna get the wrong kind when i add more. but nitrate and nitrite are both at zero water temperature is at about 75 degrees f GH-180 and KH-80. i know the gh is really high and i’m unsure how to fix it as my water is really hard and no water conditioner seems to lower it without completely covering the tank in white residue. i have no other fish besides the corys. i also feed them sinking shrimp wafers and they seem to love them. i’ll get a picture in a sec here but if you have any advice on how to get the hardness out of the water that would be helpful

 

[mrsjoannh13]

I don't know that your water parameters are bad for the corys... maybe someone more experienced can weigh in on that but I think they should be fine based on your water parameters.

I am more inclined to think the issues are tank size, number of them in the tank and the substrate (it's gravel I think?). Tank size should probably be 20 gallons with at least 5 or 6 of the corys. They like to be in groups of 6 more to feel safe, secure and happy. So the behavior could be stress related due to small tank size and not having enough corys. Also, I believe they do best with sand substrate. They have these little whiskers called barbels they use to feel around the substrate and a gravel bottom might be injuring the barbels.

Just a few initial thoughts.

 

[pepper169]

I don't know that your water parameters are bad for the corys... maybe someone more experienced can weigh in on that but I think they should be fine based on your water parameters.

I am more inclined to think the issues are tank size, number of them in the tank and the substrate (it's gravel I think?). Tank size should probably be 20 gallons with at least 5 or 6 of the corys. They like to be in groups of 6 more to feel safe, secure and happy. So the behavior could be stress related due to small tank size and not having enough corys. Also, I believe they do best with sand substrate. They have these little whiskers called barbels they use to feel around the substrate and a gravel bottom might be injuring the barbels.

Just a few initial thoughts.

Okay i was gonna get a sandy substrate but nowhere has it near me so i might have to look online. also would you be able to tell me what kind of juli corys they are? false or real? i am unsure on how to tell and i heard they like the same species so i would love to get a few more of the same kind. thank you for your help!

 

[Fishiemang]

They do that. Sometimes they'll be really active for a while together, others they will just kinda park somewhere solo.

I have a similar sub. Their barbels will be ok. Sand could be better, as the food just sits on top, but gravel they dig through.

Just keep an eye on it. It's probably fine...

 

[ClownLurch]

Get sand when you can. Get some more Corys when you can. Would be my inexpert suggestion. Corys apparently buddy up no matter what type you’ve got so Juli or false juli isn’t to important unless you’re thinking of breeding.

 

[FishGuest5123]

Agree with above. I have plenty of each Cory group. However, I have one albino and one panda that are best buds.

 

[Gypsum]

It's likely to be false julii, or C. trilineatus, because julii corys, C. julii, are very rare in the hobby. Doesn't really matter (unless you want to breed), since corys will shoal with other species of corys, especially conspecifics. However, they should be on sand and ideally, in a larger group with at least 20g of space. But the sand is critical. They will damage their barbels nosing around in gravel, which then risks infections.

I'm no expert here as I've never had to faff with hardness or softness (top tip: keep fish already adapted to your water conditions), but as far as I understand it, the only safe way to soften your water is to buy RO water from a fish shop or make it, but you need specialised equipment for that.