Julii Corydoras glass surfing because they're hungry?

[ReeseADHD]

Heyo, so I have a quick question. I have 6 Julii Corydoras in my heavily planted aquarium. They started glass surfing about 2 days ago but I figured it was because I did a water change, but they continued the behavior for several days. This morning I fed super heavy ( this isn't something I do every day, I test water regularly don't worry.) so everyone in the tank had a huge meal this morning. I noticed that my corydoras stopped glass surfing after that and they still haven't glass surfed again today. When I feed I always sprinkle food on the top of the surface first to lure voracious eaters away so I can sneak the sinking wafers/pellets in for the bottom feeders. I always make sure to watch the corydoras eat before I walk away because I worry about them not getting enough food. So this leads me to think that they were glass surfing because they were hungry because they stopped when I fed heavy? But I watch them eat every time I feed a normal amount? I tried searching the web to see if corydoras glass surf when they're hungry but I couldn't find anything on it. So I'm super conflicted on why they were glass surfing, water parameters are fine and there's no predators/big fish in the tank. Anyone have any ideas? 

[Flumpweesel]

As it was after a large water change could it have been spawning behaviour. They like to lay eggs on the glass so it can look a bit like glass surfing.

[Brian]

Are they doing the Corydoras “T”. Google it.   Once you see it you will know.   Might be spawning behavior.    Or Corydoras being Corydoras….

Good Luck 

[Odd Duck]

Cories do love to random glass surf, but I see more frantic looking glass surfing with spawning behavior.  “Normal” cory glass surfing is fast but not tense, and there are very few collisions happening.  They may follow or swim side by side, but it’s still fairly relaxed looking overall.  Spawning style has a more frantic feel to it, more intensity with a lot of bumping, and nearly always involves an extra chubby girl and 1-3 smaller, slimmer boys that stick very close to her and may do some bumping or nudging.  There may be some dashing away to plants, then returning to glass, then dashing away again.  I find overly harassed girls will dive into a very thick stand of plants in my tank to get away, and that doesn’t happen with the happy dance style glass surfing.  After a round of happy surfing, will just stop, often as a group or most of the group, and plop down together to rest.  Spawning surfing, the female will more often try to get away for a while and not plop down with the group.  She will disappear into the tank or dive through plant clumps to shake off the males for a little while so she can rest.

[Brandon p]

Mine do very often most often in the evening. Then after a water change they race around after each other

[ReeseADHD]

Thank you to everyone that replied! I think it was spawning behavior due to the large water change 🙂 again thanks for the insights 

[nabokovfan87]

On 5/24/2022 at 4:13 PM, Lucid_Reese said:

I always make sure to watch the corydoras eat before I walk away because I worry about them not getting enough food. So this leads me to think that they were glass surfing because they were hungry because they stopped when I fed heavy? But I watch them eat every time I feed a normal amount? I tried searching the web to see if corydoras glass surf when they're hungry but I couldn't find anything on it. So I'm super conflicted on why they were glass surfing, water parameters are fine and there's no predators/big fish in the tank. Anyone have any ideas? 

Mine do it literally daily.  It's just a normal cory behavior.  They also do it just to "play" in the flow. 

I wake up to this daily.  The fun days are when it's all 5 of them going to town.