Why does it.....?

Allan · Post by **Allan** » 02 Jan 2004, 01:44

This beeing the case, it seems I stand corrected on my cleaning-theory.

I will pm you my email, Coryman, hoping you will email me the part where the cory blinks.

I am really surprised on this. In could still swear that the pupilla is covered when im looking at them. Guess they blink faster than my eye can catch (excuses

)

I still have a hard time settling with the viewing-theory, but guess i have to live with that

michelle56 · Post by **michelle56** » 02 Jan 2004, 02:59

I was also wandering what kind of cory I had...
Sorry its Big!!!!! but made with photoshop.

Coryologist · Post by **Coryologist** » 02 Jan 2004, 04:36

Michelle56:

I suggest you go here: http://www.planetcatfish.com/catelog/ca ... thumbs.htm

It's fun trying to identify your catfish and you'll learn about others as you go. - Frank

Beersnob · Post by **Beersnob** » 02 Jan 2004, 19:24

Coryman wrote: michelle56, Cory's are almost always kept in good sized groups.

Ian

Ian,

There is an article about the number of Cories to keep together in the Tropical Fish Magazine. I believe the intent is to keep a large number so that the Cories are happy, but within reason of your tank confines. The three in Michelle56's 10 gallon tank are probably more than enough if she'd lioke to have other fish in that aquarium.

But I do enjoy the periodic trip to the top of the tank and then back down along the substrate. The Cories are running along the bottom and then will once in a three hour period go up to the water surface for 3 seconds and then return to swimming along the substrate. Why do the Cories exhibit this type of behavior? I figured Ian would have the best response for this.

Thanks,

Scott

Allan · Post by **Allan** » 02 Jan 2004, 20:28

The ragged fins could very well be the result of what you call the 'Black scirt tetra's, We call them 'Merry widow's here in the UK, they do have a reputation of being nippers, I don't know how many you have but they are least trouble when kept in decent sized shoals (8 -10).

The numers 8-10 was originally meant for the tetras. I think these should be kept in a decent schoal. Maybe a tank upgrade is the answer?

I have seen many breed cories in small tanks (5 gallons) in schoals on 3-4. Indicating to me that cories can thrive under these conditions. Still i think that in a cummunity tank they seem to be better of in bigger schoals, but just my opinion.

The trips to the surface has been treated many times on forum.

http://www.forum.planetcatfish.com/viewtopic.php?t=435

http://www.forum.planetcatfish.com/view ... ght=#23571

http://www.forum.planetcatfish.com/view ... ght=#14692

The fact that they are able to process oxygen through their digestion system is, i think, well accepted.

michelle56 · Post by **michelle56** » 02 Jan 2004, 23:05

that didn't really help.

I have seen 3 different cories that look exactly the same.

Allan · Post by **Allan** » 02 Jan 2004, 23:45

Try this on, Michelle

http://www.planetcatfish.com/catelog/ca ... /508_f.php

Post by **Coryman** » 03 Jan 2004, 00:19

Michelle,
your Cory's arewithout a doubt C. trilineatus and your ten gallon tank should comfortably house 6.

The reason the go to the surface is to collect a gulp of frest air, at the same time the take in new air they will usually release used air from the anus. This action takes place not because there is an oxygen defiency in the water. They do as has been previously stated absorb oxygen through the wall of the gut and I am led to believe that it is a necessary requirement. Apparently recent scientific experiments have proved that specimens that were not alowed to take in air at the surface suffered and died. I have not read the paper but would be interested in doing so.

Ian

Graeme · Post by **Graeme** » 20 Jan 2004, 16:20

Sorry to drag this up agian but here's a Piccy i must show.

Allan · Post by **Allan** » 12 Feb 2004, 06:00

Now I went through a lot of trouble myself to catch this motion on video, as i newer saw any other proof.

I borrowed a digicam with good macro ability and possibility to shoot video, and a tripod to keep it still while filming. I put up ekstra lightsources and started shooting. All in all i caught 11 blinkings.

I have no doubt that they blink all the way down. I took one of the videos, split it into pictures frame by frame. Have a look:

- First picture is where it starts the blinking, no pupil covered, but the bottom of the Iris is.
- Second picture: Here we have 60% of the pupil covered. All previous posted pics are taken between picture one and two as i have been suspecting.
- Third picture: We now only see just the top of the pupil, 90% of pupil covered below the skull.
- Last picture shows 100% pupil covered, only just a top bit of the Iris can be seen here.

This has nothing to do with seeing or focus. The eye cleaning theory seems to me highly likely, as stated all a long.

I converted the videos to MPEG and burned them on a disc. I could then play them in 1/32 speed on the DVD-player. I have had 5 people to look at this until now, including a biology student. They all back me up, and find my reasoning likely.

My computer is to slow for a good video editing program, and the video-editing i could get a hold of causes loss of resolution on the film while processing. I am working on getting unlimited server space to share original video with You (over 100 mB of blinking cory action).

Until then, all of you who have interest are very welcome to pm me Your email, and i will then send you a 1,5 mB AVI-movie that shows the action accurately. Note that this is not the same film as the shots in top of this post is from, thereby i have more than one proof.

Kr Allan

Post by **Coryman** » 13 Feb 2004, 00:32

Allan,

From the angle of your pictures it certainly looks like the iris is covered. Unfortunately I have not mastered the tekkie stuff to be able to post pictures of the action i have on video. I took my video with the camera lens central to the fishes eyes and I maintain my original theory. If you are not positioned central to the eye then you do not get the right perspective. I have spent more time prior to writing this watching my group of Brochis splendens.

Ian

sass · Post by **sass** » 13 Feb 2004, 00:44

Hi Ian

I must admit, I really can't follow you in your critique here. The image, although it's not the best quality, is showing that the pupil is covered by the skull. You don't have to be at level with the fish to see this happen. As I see this shot, you start out with seeing a full eye and then over the next three shots the eye rolls over so the pupil is covered. The angle of the shot has nothing to say here if you ask me.

Regards Sass

Post by **Coryman** » 14 Feb 2004, 03:00

Sass,

I have just spent several hours trying to get pictures on line to show what I have on video but I just do not know what I need to do. I have taken the video from camera onto my Hard drive, then using iMovie have selected 12 frames and saved them as jpg's but I cannot get them to load on my site, I will figure it out!!

I filmed my biggest fish, Brochis splendens to get the best possible results and I am sorry but I stick by my original theory and you do need to be level with the eye to see the exact movement.

If you guys are going to be at the Corydoras Club meeting on the 6th March I will have my lap top computer with me with all the video clips on.

Ian

sass · Post by **sass** » 14 Feb 2004, 03:21

Hi Ian.

I've tried to capture this blink with an SLR equipted with a macrolens but can't get the timing right. The magnification I use is quite good since it is true macro. And when I look in the viewfinder on the camera, I see that in some cases the entire pupil is covered by the skull. It's not always but it does appear. But looking forward to see what you have got on video, and I am coming to that meeting and looking forward to hear your lecture.

Post by **Coryman** » 14 Feb 2004, 21:58

I have just quite by accident found out exactly how much movement a Corys eye has.

I have been catching a number of fish in readiness for selling them on at tomorrows (Sunday) CSG Auction and with some fish it is easiest to use my hands to select them. While handling a couple of the larger specimens i noticed the eyes moved down when I turned the fish on its side, so I moved the fish into various positions to determine the maximum amount of movement, the result being only one third of the iris is covered by the lower edge of the shroud.

I then tried the same thing with several fish and the result was exactly the same. I will now be able to take pictures and show you the results.

ian

Post by **Birger** » 18 Feb 2004, 06:09

In an earlier post someone mentioned maybe getting a biologists opinion on the eye subject, I contacted an old friend Joseph S.Nelson (author of Fishes of the World) who still does research out of the Univ.of Alberta and asked him about the eye subject and these were his words

Catfish eyes-- yes, i have seen that also as well as in some other
bottom fishes. I have no idea but my guess is that its a way of looking
around (without having to move their head & drawing attention from
predators).
IF I can think of anything else I shall let you know!

Its kind of late and doesn't really solve anything but I thought I would throw this in anyway.

Birger

stibolt · Post by **stibolt** » 18 Feb 2004, 08:25

My crayfish (well, it sounds far out, but. .) does the same motion as my corys do. he jerks his eyes in the same odd fashion and he always does it while heÂ´s cleaning his body and eyes with its legs. Obviously that doesnÂ´t mean that itÂ´s excately what the corys do, but on the other hand thatÂ´s a thing that makes me think that perhaps itÂ´s a cleaning fashion

OR. . perhaps itÂ´s like when we stretch our muscles.

Either way, IÂ´m looking forward to your video, Ian.

pleco_breeder · Post by **pleco_breeder** » 18 Feb 2004, 08:34

Stibolt,

The cray fish is also looking around. The difference would be that it is looking for predators. Whereas the current suggestion for corys seems to be searching the local area for food, or at least that's my suggestion anyway. Crayfish are quite vulnerable while cleaning and are not adapted for areas as barren as most fish tanks. Their common habitat would include leaf litter or creek banks where there are numerous places to dash to.

Larry Vires