One Schwartzi doesn't hang out with the rest

[realgwyneth]

I've got 7 Schwartzi corydoras in a decently planted 65 gallon (36" x 18" x 24"). One little guy always seems to be off by himself, while the other 6 happily hang with a Zebra loach. The lone ranger doesn't seem stressed, and it will go hang with the others during water changes. I =think= it is actually the oldest of the group. Should I be worried? Will getting one or two more help?

Most recent water parameters: pH: 7.3, Ammonia: 0, Nitrites: 0, Nitrates: 10, KH: 80, GH: 180
Tank mates include 8 cherry barbs, 3 zebra loaches, a lemon tetra (sole survivor of a school), a kribensis, and some ancient red-eye tetras. (What can I add with this mix of mostly South Americans when the lemon and the red-eyes are gone?)

 

[Colin_T]

pictures and video of the fish so we can check them for disease?

 

[realgwyneth]

pictures and video of the fish so we can check them for disease?

I'll try to do that here. I'm not sure how to post a video. Grumpy isn't being real cooperative today.

 

[realgwyneth]

Maybe uploading a video from this source will work:

https://www.pinterest.com/pin/99219998034980564/

 

[Colin_T]

The fish in the picture and video looks healthy. Can you post another video showing the other fishes?

There's no reason for it to swim off on its own apart from if it's a different species to the others or it just doesn't like them, but Corydoras like company so maybe it's just a loner.

 

[realgwyneth]

The fish in the picture and video looks healthy. Can you post another video showing the other fishes?

There's no reason for it to swim off on its own apart from if it's a different species to the others or it just doesn't like them, but Corydoras like company so maybe it's just a loner.

Thanks the feedback, @Collin_T. Thinking back on his history (her? its?), Grumpy came home as part of a group of 6 in 2020, but five died within a week. No other fish in the tank had any issues, so maybe that stress hormone that corys can give off did them in, or who knows? We've since built up the group one or two fish at a time (and plan to get one or two more). The most recent one came in about 8 months ago. Maybe Grumpy just never really bonded with any of the new ones? He will school with them during water changes, but as soon as it calms down, he's back off by himself again.

I'll try to get a video when the light comes on. In the meantime, here's a photo of the other six along with their honorary cory (the zebra loach peaking out from the rocks) who schools with them. Grumpy is every so slightly larger than the two in the foreground. By the way, about 1/3 of the substrate is now sand, a work on progress, but the these six corys seem to prefer the old gravel to the sand.

 

[Colin_T]

The loner has much darker markings than the others. It might be a sub species, maybe it was sick when the first group died and it recovered but has permanent health issues. Maybe it's stressed over losing its friends.

Monitor and see how it goes. It looks physically healthy and might just dislike the new tank mates.

 

[realgwyneth]

The loner has much darker markings than the others. It might be a sub species, maybe it was sick when the first group died and it recovered but has permanent health issues. Maybe it's stressed over losing its friends.

Monitor and see how it goes. It looks physically healthy and might just dislike the new tank mates.

Thanks. I guess I hadn't noticed that his black mask is wider than the others'. I am definitely keeping an eye on him, and I'm hoping to add one or two more the next time they become available.