Surfing Corys

[Tom Marquis]

Experienced Aquarist here with a question:

perfect water conditions. 200L tank. Only 10 adult corys and 3 adult Discus in the tank. Been in the tank together for over 2 months.

If the corys aren't eating, they are surfing the rear glass. Fulltime. They are extremely healthy. As are the Discus.

If there is food available, they hit the bottom and act perfectly normal until the food runs out.

Then, we're surfing! All of them together.

As I said, experienced aquarist. I typically watch corys to determine the water conditions without a full test. They are great indicators of the water conditions.

This one is beyond my knowledge. Ideas or help? Are they playing? Never experienced this sort of constant play. They are unable to see a reflection of themselves due to the rear glass darkness. So not chasing their reflection.

Thanks! Tom

 

[MichaelJ]

Schooling fish such as Cory's are prone to repetitive behavior... I think they might just be "playing"... you could possibly put a plant or some hardscape close up against the rear glass and see if that breaks the behavior. I assume this is a planted tank.

Cheers,
Michael

 

[Conort2]

Ideas or help? Are they playing?

They normally do this either when they’re first added to an aquarium or when they’re in the mood to spawn. The males will chase the females around and they will pace up and down the glass in a group.

 

[PARAGUAY]

I think if not spawning and a waterchange can bring this on, they just settle ,my Bronzes sometimes make repetitive up to the surface periods but then just stay on the substrate, no idea unless it's a pecking order thing, just a guess

 

[Conort2]

What species of corydoras are they?

 

[JeffK]

Do you have a full tank shot? They could be stressed out if your tank doesn't have enough hiding places.

 

[Tonalscape]

Mine usually surf in pairs or trios and based on results, it is a mating pattern in my case. The females are larger and being chased if I look at the behaviour closely.

I've seen glass surfing from other fish in the past, solo. There wasn't a source of stress that I could point to in those cases so I figured it was just a temporary obsession.