Corydoras confusing behavior.

[Karen B.]

I left my fish room for 2 weeks. Automatic feeder on, friend was coming to check on the fish every 3 days and did a WC.

I came back and my tank was ok - a bit more mulm than usual as I always gravel vacuum when I do my WC but that’s it.

So I did a 30% WC/Gravel vacuum… but I accidentally put twice the amount of easy green so I immediately followed with a 15% wc.

Since then, my Corydoras’ behavior are all over the place. Some are chilling in their cave. The babies are grazing on everything for food, some are breeding/laying eggs, some are swimming like crazy chasing each other from one side of the tank to the others and others are glass surfing. They haven’t glass surfed in so long, it always stresses me when they do.

Planted tank, temp a bit higher then usual (77 instead of 75.5), HOB aqueon 30 filter serviced 2 days ago + sponge filter. 0/0/25 (Kinda high, I am usually around 0-10). pH a bit low at 6.6, kh used to be 0 but I added a bit of Seachem alcaline (half the dose) and it raised my kh to 40. GH used to be 300, now it’s somewhere between 150 and 300.

The other fish (3 honey gourami and 6 chili rasboras) are behaving normally.

Should I worry? Or are the Cory glass surfing just stressed because of the small changes in parameters while the others don’t care? Should I be doing something?
 

 

Edited January 9, 2022 by Karen B.

[Levi_Aquatics]

I wouldn’t be too concerned. I have overdosed easy green before without issues. If you are really concerned you could do another water change to dilute it. 

[Ken]

Corys just love a big water change. They're just fine. On the EZ Green double dose... I do that whenever the plants look like they need a little pick-me-up, I am heavily planted. So long as you don't drive the nitrates too high it won't hurt anything.

[Patrick_G]

On 1/9/2022 at 2:24 PM, Ken said:

I do that whenever the plants look like they need a little pick-me-up, I am heavily planted. So long as you don't drive the nitrates too high it won't hurt anything.

I also do a double dose when needed. George Farmer recommends a large weekly doses of liquid ferts combined with large water changes. 

[Cinnebuns]

@Ken I don't wanna hijack the post so just 1 question. I have heard that doing a wc with cooler water helps encourage cory cats to spawn. Should I also do a larger wc to help encourage them?  If so, how large? 

[Guppysnail]

Changes in water temp hardness or even just large water changes often incites breeding behavior in corydora. What you described sounds normal based on my experience 

[Ken]

I feed them frozen blood worms (lots) for a couple days then 40-50% water change 3-4 degrees cooler than the tank then feed them extra for another couple days. It usually works.