LittleFizz

Ok, I saw one of my corys blink so I said to myself "It's ok Sarah, your nuts. Fish don't have eye lids!!!" then I saw it a second time and thought... Maybe they do blink... But then the THIRD time. I knew it had to be true. I told my mom and she laughed at me. But then she saw it too!!! So whats going on here? Do the corys blink or are me and my mom seeing things? Lol sorry about this crazy post. Have a happy and safe new years everyone!!!!

Dino

They actually roll their eyes back into their skull.
It does look like they are blinking.

Barbrella

I think that "winking" is one of the things that makes corys so cute!

As you realize they have no eyelids, therefore can't blink. They do make rapid eye movements and roll their eyes searching for predators and that makes them look like they're winking!

LittleFizz

Lol wow!!! Thanks for the quick response! ... Weird. Well I'm glad I know now! Lol it's pretty neat.

armadillo

Yeah, they do a lot, it's super cute.

But how do we know it's looking for predators and not food.

Also, what is the purpose of rolling them in the back of their head? Cleaning? If so, why don't other fish do it? Mmmmh. Worth researching. Interesting.

armadillo

Here's a few theories I've found here and there.

• 'What they're actually doing when they are blinking, or winking, if forcing air into their gut, where the oxygen will then be extracted. They do this more out of instinct than anything else, because in the wild, they live in murky, low oxygen water, so it is necessary for them to do this. ' (Kathryn003, Youtube, search for cory blinking). Don't see how this eye movement would help in oxygen extraction?

• Here's another interesting one: 'Perhaps the Corys regurgitate their food and use their eyeballs to help crush their food like frogs do?' (Quatermass, http://www.practicalfishkeeping.co.u...hp/t-2286.html)

• 'Just a thought, but I seem to recall on a 'wild life on one', that frogs can only see movement. Maybe these are the same, and need to move their eyes to refresh what they see? ' (same thread, from Wezdawes)

• And another theory (same thread, from Naiad) 'Maybe the 'blinking' cleans particles of dirt off the eyes. It is mostly done by bottom-feeding fish which often stir up mud when feeding. Goldfish do it too, and they do it more when their water is changed, maybe the new water irritates their eyes.'

• I like this one: 'Firstly if you look at a cory head on, you will see that the eyes are set quite high up on the head and when the eye is in its natural position the fish is actually looking slightly upwards. Those of you that are familiar with the fish eye lens of a camera, will know that the only true focal point is on the horizon. So to to focus on lower or higher objects the camera needs to be raised or lowered. I think the Corys action is just doing the same thing in order to get a good accurate view of its surroundings.' (Coryman, http://www.petfrd.com/forum/archive/...p/t-15704.html)

• In this one (http://www.theaquariumwiki.com/Corydoras_sterbai), they speculate that it's to check the substrate.

tkfury

Maybe its just because I only notice it but it seems my cories only "blink" when they're looking straight at us. I've watching them and never noticed any eye movement unless they were facing someone looking in on 'em. I like to think of it as them saying hi - but then again when my cat sticks his tongue out I take it as he's sayng I love you anyways

Dino

I am in the clean the eye camp.
Most cories come from areas of fine substrate.

armadillo

I have to admit I'd hate for it to mean that they're on the watch for predators whenever check them out. That's the one I'd go for too, although someone made a point about why would they need to clean their eyes, when they're in a liquid medium anyways.

Also, what's that about the 180 degree rotation. I don't get the point of that. Mind you, that could also be consistent with cleaning.