Peppered Cory’s and Water changes

Hi everyone, Me again!

I have a planted 125 G tank - I’ve been doing between 30-40% water changes weekly or every week and a half. (Depending on nitrates - sometimes less)

Last week (see my last post if you want) I had an issue with not dosing enough water conditioner and Chlorine killed one of my fish and wiped out some of my BB (transitioning to the bigger tanks from a smaller tank is more complicated when it comes to that). It’s all good now because I had back up media to add.

Parameters are 0,0, and 5-8 (after today’s water change for nitrates)

I just did a water change today, dosed enough water conditioner (tested tap water before to see chlorine and chloramine levels and added WC along with the new water)

tank has tested all good in terms of chlorine etc. the newly added water is the same temp as the tank water (it was the same when added). I add water by pouring through a large strainer so I don’t stir things up or stress them too much.

However my peppered corys (2) are floating at the top on their side. They do this every time that I do a water change. All of the other fish are fine.

Is this something particular to them and their swim bladder? I saw something that says pouring water through a strainer could actually OVER oxygenate water, is this a thing?

I know peppereds have gas problems (swim bladder etc).

 

Do you see them surface frequently during the waterchanges or short after?

 

Towards the end / Shortly after the water change. They almost never surface otherwise (maybe like a quick burst a few times a day - if that). It’s been approximately 1.5 hours since the water change and the two peppereds are still laying on their sides at the top of the water. They swim down every so often (but not far) and then they float back to the top to rest on their sides. Similar to an issue with their swim bladder, but this is only during a water change.

So it has to be something with the change but no chlorine / chloramines, same temp water, all put through a strainer so as not to disturb the tank too much.

Is it possible to over oxygenate the water and to affect their swim bladder for a short time?

 

It isn't their swimbladder. Corys take in air in their intestials (a second breathing system).This happens in cases of stress, excitement, etc.....
Sometimes they take in too much and start to float. Often a good fart is enough and they'll be okay.

Only we need to research what is causing the stress that causes this.

 

Thank you for the input! It may just be the water change itself as the stressor. Good to know about the Cory’s. Hopefully these guys let out a little fart soon then. How silly lol