Corys acting strange after water change

[Mercfh]

So I witnessed a weird thing today, I did a WC using the python (About 25% on my 29G since I had a slight .5 ppm ammonia spike from adding new fish). But afterwards the Corys (all of them) were like "floating" in weird positions...and it almost looked like there was a bubble in their abdomen. It's almost like they were struggling to "stay down" and would just sorta float around.

All of them acted like this but no other fish did. The water temp was similar enough, and while my tap pH is 8.2 my normal pH in my aquarium is 7.8, and it was only a 25% WC.

There are 2 factors however.

1. I was having trouble with the python, so the WC took a good 30+ minutes but surely the tank wouldn't have ran out of oxygen by then?

2. I did forget to dechlorinate the water (I know I know, major Facepalm moment...I think because I was fooling with the python to get it to work). The new water was maybe not chlorinated for 1.5 hours before I realized.

They did eventually come back to normal and seem to be swimming around like normal.....but they almost looked stunned. Any ideas? I mean obviously swim bladder disease doesn't develop in 1 hour in all of them..so maybe shock from the chlorine maybe?

Do you think they will be ok since it was only an hour (Obviously I need make sure i set the bottle out before WC so I don't forget). But im curious what could've caused this.

Ive seen similar issues that other people mentioned cory's acting weird after WC's before. FWIW I did a water change before with the same group (Using manual gravel vac before) and they were fine....but I did dose the dechlorinater right before.

 

edit: FWIW They were ALL fine before the WC.

 

Edited January 8 by Mercfh

[Fish Folk]

If it is cold where you live, it may be that your tap water is holding a lot of gasses. You know how when powder of any sort is mixed into a cup of water it helps it to dissolve faster if the water is warm or hot? The chemistry principle works in the exact reverse with air gasses mixing into water flowing through pipes: if the temperature drops, tap water coming into your house drops, absorbing a lot more gasses.

The old aquarium masters always used to say “rest your water.” By that, they always meant … fill up a 5-gal bucket, leave water to “rest” for 48-hours before adding to your aquarium. So you could draw ca. 5-gallons _out_ with your Python, then use a large measuring cup or specimen container to refill from your clean bucket of rested water. This allows tap water to “gas off.”

Edited January 8 by Fish Folk

[TOtrees]

@Mercfh what you're describing, what you saw your cories doing and your description of forgetting to dechlorinate, seems to be the whole story. Ie i don't think you're missing anything. I have seen exactly the same, although it occurred a wee bit faster. I removed water, added new water, fish went all wonky and spiraling, realized I forgot to dechlor, added dechlor, recovery over 15-20 mins or less. 

I would only caution to keep a closer eye on things for a few days. If the amount of chlorine in the water was enough to cause the fish to respond that way, it could be enough to impact your bacteria colonies. So don't feed for a day or two, and keep an eye on things. 

[jwcarlson]

Sounds like a dechlorination issue.  Lots of factors as to why just the corys would show evidence of it, but that's the best bet.  I'm sure we've all done it.  I've done it on my discus and almost killed them.  It's pretty easy to forget.  I will say that fish might seem "off" for quite awhile after that happens.

[MattyM]

Also, when adding de-chlorinator to an entire tank like this, make sure you add for the full volume of water - not just the new water added. So, if you have a 20 gallon and removed/added 5 gallons directly to the tank via a python, treat for 20 gallons. This ensures there's enough de-chlorinator to go around the entire tank. 

[Mercfh]

On 1/8/2024 at 1:03 PM, MattyM said:

Also, when adding de-chlorinator to an entire tank like this, make sure you add for the full volume of water - not just the new water added. So, if you have a 20 gallon and removed/added 5 gallons directly to the tank via a python, treat for 20 gallons. This ensures there's enough de-chlorinator to go around the entire tank. 

That's what I usually do, but the python (which is also new to me) was giving me problems so I think I was messing with it too long and it threw me off balance. Is it likely the dechlorinator missing for an hour substantially hurt them?

On 1/8/2024 at 5:42 AM, Fish Folk said:

If it is cold where you live, it may be that your tap water is holding a lot of gasses. You know how when powder of any sort is mixed into a cup of water it helps it to dissolve faster if the water is warm or hot? The chemistry principle works in the exact reverse with air gasses mixing into water flowing through pipes: if the temperature drops, tap water coming into your house drops, absorbing a lot more gasses.

The old aquarium masters always used to say “rest your water.” By that, they always meant … fill up a 5-gal bucket, leave water to “rest” for 48-hours before adding to your aquarium. So you could draw ca. 5-gallons _out_ with your Python, then use a large measuring cup or specimen container to refill from your clean bucket of rested water. This allows tap water to “gas off.”

Im in Kentucky so it's cold right now, but I did such a small water change (25%) I don't think it could be a ph/temp issue. Especially since I had done it before and they didn't do this. I have a 55G as well so I don't see how I could realistically do "resting buckets" anyways for something like that.

 

EDIT: I did read something about like there being too many bubbles or microbubbles in the water? I've never heard of this? (But I did notice bubbles in the corys abdomen....but maybe there were over gulping for air or something)

Edited January 8 by Mercfh

[nabokovfan87]

On 1/8/2024 at 11:17 AM, Mercfh said:

Im in Kentucky so it's cold right now, but I did such a small water change (25%) I don't think it could be a ph/temp issue. Especially since I had done it before and they didn't do this. I have a 55G as well so I don't see how I could realistically do "resting buckets" anyways for something like that.

In winter I use the sink to try to get the temp appropriate water. Given the situation, unless you're running a heater in some sort of conditioning chamber you're talking frigid water going into the aquarium and while it can trigger spawning, has a lot of oxygen compared to the tank itself, there is other things in the tank apart from the corydoras that might not enjoy the drop.

Dechlorination is definitely at play here. I wanted to ask for the sake of full clarity if you're in a local well or if you have any idea if the water company might be flushing the pipes with  some sort of chemical.

On 1/8/2024 at 11:17 AM, Mercfh said:

Is it likely the dechlorinator missing for an hour substantially hurt them?

Yes, absolutely possible.

[Mercfh]

On 1/8/2024 at 3:02 PM, nabokovfan87 said:

In winter I use the sink to try to get the temp appropriate water. Given the situation, unless you're running a heater in some sort of conditioning chamber you're talking frigid water going into the aquarium and while it can trigger spawning, has a lot of oxygen compared to the tank itself, there is other things in the tank apart from the corydoras that might not enjoy the drop.

Dechlorination is definitely at play here. I wanted to ask for the sake of full clarity if you're in a local well or if you have any idea if the water company might be flushing the pipes with  some sort of chemical.

Yes, absolutely possible.

Not using well water. im sure our municipality uses some sort of chloramine though.

Would putting in some API Stress coat maybe help?

[nabokovfan87]

On 1/8/2024 at 12:06 PM, Mercfh said:

Would putting in some API Stress coat maybe help?

It is similar to dechlorinator but has added aloe vera in there. It wouldn't help or hurt the situation I don't think. Rapid changes in parameters, temp, pH, etc. likely were at play here as well. It caused something to happen where you have swim bladder issues from your description and beyond that I just don't have the knowledge to expand on specific details.

I hope they recovered and are doing a little better. Sort of like drinking a soda too fast and you feel excessive internal pressure.  People have used things like epsom salt if that is for certain the cause of the discomfort, but absolutely do your research on what type of salt is best (aquarium salt vs. Epsom salt) and how to proceed with that methodology if that is your last resort.

[Mercfh]

On 1/8/2024 at 4:36 PM, nabokovfan87 said:

It is similar to dechlorinator but has added aloe vera in there. It wouldn't help or hurt the situation I don't think. Rapid changes in parameters, temp, pH, etc. likely were at play here as well. It caused something to happen where you have swim bladder issues from your description and beyond that I just don't have the knowledge to expand on specific details.

I hope they recovered and are doing a little better. Sort of like drinking a soda too fast and you feel excessive internal pressure.  People have used things like epsom salt if that is for certain the cause of the discomfort, but absolutely do your research on what type of salt is best (aquarium salt vs. Epsom salt) and how to proceed with that methodology if that is your last resort.

Fortunately they seem ok now. I would say they were acting odd for about 2 hours after the event. It's gotta be the dechlorinator because i've done WC's before and they've had no issues. And even though my pH is higher out of the tap.....I only did like a 25% WC and the pH isn't THAT different.