New corys excessive surface-breathing, looking for advice

I finally found some elegans to add to my one lone one in the pool; got them yesterday and they're in quarantine, along with a couple of new paleatus (to add to an existing shoal of 8-10.)

Right out of the bag the elegans were surface-breathing exclusively - coming up regularly every 10-20 minutes, no gill movement at all while submerged to indicate normal breathing. The water is fine (0,0,0, being just filled with water to receive them and with a mature sponge filter added), and the two paleatus are fine, not surface-breathing (at least no more than any cory usually does.)

When they still didn't start breathing normally after an hour or so in QT, I also rounded them up and gave them a short methylene blue bath. Was late by the time I put them back in QT, didn't have a chance to observe them further.

Looked in on them briefly this morning, had lost one overnight (kind of expected, one had arrived trapped in a corner fold of the bag, they were double-bagged but not inverted). Did a quick 50% water change in case of excess ammonia from the death, and saw that they are still surface-breathing this morning (while the paleatus are still fine.)

They don't have flared gills, haven't seen any of them flashing, nor are they just sitting on the bottom with clamped fins; most of them are actively shoaling with the peppered (moving when they move, resting when they rest). Haven't run into this with corys in the past, so not sure what I should be looking for (or potentially looking to treat them for.)

 

I would guess that whatever you have them in doesn't have as much oxygen as they are used to. They will probably survive as they can breathe from the surface but I would suggest adding a couple of air stones. A video would also be nice to see exactly what they are doing.

 

There's a large sponge filter providing bubbles, and it's a shallow container with lots of surface area (it's holding around 15 gallons, with 2 small paleatus corys and now 4 elegans, all of which are around 1.5 inches in size.)

Can't get video at the moment, but even if I did - it would be 10 to 20 minutes of them either sitting still or moving around, then a dash to the surface for air, then another 10 to 20 minutes of sitting still or moving around.

They are acting like they are avoiding using their gills, rather than like there isn't enough oxygen (lack of oxygenation usually results in both: gill-breathing, sometimes rapid, with additional boosts from surface-breathing). They are not using their gills at all, that I can tell - their gill-covers are closed on both sides, and are not moving even when they are at rest.

Which says to me that either their gills are irritated by something (can't be the water or the paleatus would also be affected), or there's some other reason they are choosing to surface-breathe over normal gill-breathing. But they also aren't flashing like there is something irritating their gills, as I'd expect they would with parasites, for example.

 

Several Coryspecies show this in stress or excitement. Personally I expect it to end as they are adapted a bit.

Got a pic of the fish ?

 

Sounds like oxygen deficiency in the water. How big is your QT tank and how many total fish in it? Adding air stones or an HOB filter which breaks the surface tension will hopefully fix.

 

Several Coryspecies show this in stress or excitement. Personally I expect it to end as they are adapted a bit.

Got a pic of the fish ?

No, but I will be happy to get some later today if you want them.

I thought the same as well, that it might be stress or even just making up for poor oxygenation in the bag; but the lack of gill-breathing between surface breaths is what's concerning, as well as it continuing into this morning.

I'm presuming these are potentially wild-caught, since elegans aren't that common in stores (at least none that I've been into). And I know I don't have a lot of experience with all the potential issues of wild-caughts (beyond intestinal parasites).

I will say they aren't terribly skittish, in fact one came over and was investigating near my hand as I was siphoning water out this morning. But can't tell how much of that is a dither effect from the paleatus, taking their cues from them.

 

Sounds like oxygen deficiency in the water. How big is your QT tank and how many total fish in it? Adding air stones or an HOB filter which breaks the surface tension will hopefully fix.

Probably cross-posted with you from above, but there are now six fish total. (There were 7; 2 peppered, 5 elegans. Lost one of the elegans overnight, but likely for a different reason. One of them had gotten trapped in a bag fold during shipment, and I expect that's the one I lost.)

All of them around 1.5 inches in size.

They're in a 26 gallon tote that is filled over halfway, probably 15 gallons. Plenty of surface area. The QT was set up with Prime as I received the fish, adding a large air-driven sponge filter that I keep in a mature tank for just such occasions. The sponge filter provides lots of bubbles/surface agitation.

Only the elegans are surface-breathing, the paleatus are not.

The elegans also do not seem to be gill-breathing at all, which says (to me) that they're avoiding using their gills for some reason, rather than that they are not getting enough oxygen via their gills and need to supplement with surface breaths.

 

No, but I will be happy to get some later today if you want them.

I thought the same as well, that it might be stress or even just making up for poor oxygenation in the bag; but the lack of gill-breathing between surface breaths is what's concerning, as well as it continuing into this morning.

I'm presuming these are potentially wild-caught, since elegans aren't that common in stores (at least none that I've been into). And I know I don't have a lot of experience with all the potential issues of wild-caughts (beyond intestinal parasites).

I will say they aren't terribly skittish, in fact one came over and was investigating near my hand as I was siphoning water out this morning. But can't tell how much of that is a dither effect from the paleatus, taking their cues from them.

Fish in problems only rapid breath, not slow breath. To be honest I have a feeling you've napoensis (mine were sold as elegans)

those are tankbred

 

Fish in problems only rapid breath, not slow breath. To be honest I have a feeling you've napoensis (mine were sold as elegans)

those are tankbred

You could well be right, I don't see them in stores so haven't really had any to compare to. (Stores here still sometimes label any spotted cory as punctatus as well though,, so that can be equally dubious as a reference).

I pulled them out for some pics and video. In video closeup I could finally see them gill-breathing; they move the operculum so little that it's basically imperceptible to the naked eye (mine, anyway.) The more rapid breathing in this can't really think too much of, since I had just caught them and put them into a smaller container for pics.

Pics - I'm not too worried about them at this point, they're all quite lively this afternoon and I had a heck of a time getting shots with some or all of them sitting still.

Given that they also didn't freak out and go ricocheting off the sides of the keeper when I put them in there by themselves, I'd also agree that they're likely tank-raised. One has a gold-ish under-color, the others more silver/gray under-color.

 

Nope, you got yourself some elegans.

I think their heads / gills are "too red" so this might be caused by the pollution in the bag. Personally I suspected you've just got them out of that bag in time and the excessive surface.breathing might be cause of they're recovering.

As said slow breathing is a plus. Let them adapt and keep an eye on the redness.
Being wikdcaught I'd advise to start feeding with living or frozen (defrosted) food.

You've got you some awesome fish.

 

BTW I watched the pics again and noticed at least one is pretty thin. Think.about deworming (and fattening up with the mentioned food)