Cory cats acting strange

[GamerGoldfish2]

I recently moved and redid my tank with fluval stratum. I let it cycle for a week after adding in all the necessary chemicals. I have a few corycats and I've noticed them moving very strange, they spend as much time swimming middle and top as they do botom. They have never done this before and I have had the tank for over a year now. It might be lack of hiding places, they have plants and a cave I 3-D printed out of PLA plastic, which is entirly fish safe. I will send pictures as soon as possible.

 

[Naughts]

Seems like they don't appreciate the new substrate. Playsand is recommended for cories so that they can sift it through their gills while feeding, and because it is smooth and clean. Coarser substrates harbour bacteria that damage the barbels.

 

[Byron]

I agree. The choice of substrate was unfortunate; the manufacturer and their allies promote these things as safe, but they certainly are not. It would be best to move the cories to a tank with soft sand. Playsand works very well. There are some fish that do not appreciate a move to a new tank, and cories are certainly one of these. That may explain the behaviours, but the bottom line is the substrate is likely to cause problems.

 

[GamerGoldfish2]

Thank you. From what I've seen their natural substrate in the wild consists of sharp gravel. I did some research and found that they swim middle when they are in a new envorment. As I am typing this I am watching them and have not seen them swim unaturally all day since I got home. They were glass surfing and not in the middle of the tank.

 

[Byron]

Regardless of the acclimatization aspect...no cories in their natural habitat live over anything but sand, or mud/mulm, or a sand mixture. None. Anyone saying differently does not have the slightest idea of habitats. I am not going to argue scientific fact.

 

[GamerGoldfish2]

Is Aquarium Co-op reliable?

 

[GamerGoldfish2]

Also, why does every article I find from many different sources say that only sand is a myth. Not trying to be arugmentitive, but what makes you more right than them?

 

[GamerGoldfish2]

Article I found :https://www.aquariumcoop.com/blogs/...corydoras can,factors like poor water quality.

 

[Byron]

I am correct here because I have spent considerable time doing research from those who know, the collectors, ichthyologists, biologists who have worked with every so-far discovered species of cory.

I had a feeling that misleading video on AquariumCo-op would likely be behind this. Ian Fuller, who is the recognized authority on Corydoridae put the lie to the video. It is misleading because it shows a handful of "gravel" which the text says is the substrate. But that is false. I told you earlier that some species liv over a mixed substrate, and the one in this video is such a cory. And if you take a handful of substrate from another area it would be sand. There is actually a fair amount of sand in the video site, but of course they do not tell you this because it does not suit their purpose. If any cory were actually found over sharp substrate, I can assure you their barbels would show it. I had this occur some years ago when I foolishly set up a tank with Flourite; within one week all the 12 cories has stunted barbels, and one panda even had about a quarter of its lower jaw sliced off. They all recovered when moved to a sand substrate tank, and lived for years.

Ian Fuller has been collecting cories and spawning dozens of species for 60 years. Heiko Bleher has been exploring and collecting fish from probably ever accessible habitat in Amazonia and beyond. They will both tell you without any reservation that you mut have soft sand. Cories filter feed; they take up a mouthful of sand (or mud/mulm), extract any food bits they might find, and expel the sand through their gills. This is how they feed, it is a prerequisite programmed into the genetic code of each cory species. To deny them this inherent need is inhumane.

As for internet sites, many are false and unreliable. Any idiot can set up a site these days. That does not mean they have the slightest idea of fish requirements. This forum aims to correct the misinformation, and there are reliable sites...for cories there is pre-eminently Corydoras World (Ian Fuller's site) and it has a FB page, there is Planet Catfish, and there is Seriously Fish.

 

[GamerGoldfish2]

ok thx

 

[TwoTankAmin]

I consider myself fortunate to have met Ian briefly at CatCon. I wanted to shake his hand and thank him for all the great help and information he had provided to hobbyists the world over.

He is a member on Plantetcatfish and he has posted on the subject of cory substrate there on a number of occasions. Here is one such comment in a thread on PC which had, once again, brought up the subject of sand v.s. gravel for corys.

Re: corydoras and gravel/sand​

Post by Coryman » 13 Sep 2014, 14:19

Just my 2 penny worth and bringing the topic back to the title "corydoras & gravel/sand"

There are many natural area where Corys are found over gravel, but this is not rough like road chip pings but smooth pebble like. The size can and does vary from 1 to 2 millimetres to large boulders, but from what I have experienced and seen in reports there are also sandy areas.

The main thing is that what ever substrate you use it should have smooth rounded edges.

Ian

Corydoras World

Go Wild Peru

from https://www.planetcatfish.com/forum/viewtopic.php?p=278588#p278588

If I remember exactly what he had said collectively over time in PC going back a number of years was basically this. Corys find their food using their barbels to taste it. When the substrate grain/gravel size gets too large, food slips deeper into it. And this results in the corys having an increasing chance of scraping their barbels as they root in the substrate searching for food. And this opens them to infection and barbel erosion.

This is compounded when the grains/pebbles have rough surface or sharp edges. Fine, rounded gravel and smooth grained sand tends to keep the food on or very near the surface. So the corys do not damage their barbels. Depending on the size of the cory species and then the grain size of sand, they may or may not sift it. Fine grained sand is best for filtering.

I have kept corys on sand and on a small size, rounded and smooth pebbles. My sand is Carib Sea Torpedo Beach and my gravel is the very old Estes Bits of Walnut aquarium gravel. (Walnut refers to the color.) They also made a larger size called Walnut gravel. Both were coated which made them extra smooth and I have used both and kept cory on both. I like the look of the Bits more.

My corys kept on the sand or the small Estes gravel had (no longer kept) or have long healthy barbels. I have never seen them sift the sand as it is a mix of grain sizes and the larger grains may be too big to sift for all but the largest corys or Aspidoras.

Torpedo Beach​

Typical Size: 0.5 – 2.0mm
Average Density: 94 pounds per cubic foot

 

[GamerGoldfish2]

So longer barbels = Healthier?

 

[GamerGoldfish2]

My substrate is smooth

 

[Byron]

It is the size of the substrate grains that matters most. Here is one of Ian's videos on how cories feed. You can see the fish upnds itself deep into the soft sand, and the sand is being expelled through the gills. The fish cannot do this in gravel.

 

[GamerGoldfish2]

I noticed this when I had sand. Will BioStratum work? The pellets are something like 0.5 to 1mm.