Corydoras sterbai Shipping problems with adults

[apistomaster]

I have tried shipping C. sterbai twice and each time was a disaster.
The first time I tried was several years ago and I was going to send them via UPS but that is when I discovered UPS and FedEx required pre-approval for account holders to ship fish. I had a few hours of errands to run but by the time I got home their water had become milky and frothy and almost all the fish died as if I had exposed them to a neurotoxin.

Then last week I sent 15 adults, my breeding colony, via USPS Express 2nd day delivery. I used a full sized fish box, double bagged box liner bags, two gallons of water and the recommend dose of Jungle bag Buddies. All the fish arrived DOA. I am not used to loosing the fish I ship.
Does anyone have any experience with shipping large Corydoras sterbai successfully?
I have shipped many other species of Corydoras without similar problems so I don't know what else I could have done differently.
They seem to be exuding a toxin like some of the Marine fish like Trunk Fish or Box fish.

[jac]

Here in Holland corydoras species are never bagged together with any other fish. They seem to give a toxin when stressed that can kill other fish. If the corydoras are bagged you will often see that they put in some coal to suck up the toxin.
Maybe the bigger the fish the more toxin they will release when stressed.

[mummymonkey]

Yes this is a known problem with C. sterbai and some other species also - C. gossei is bad for it. I'm always wary of bagging up adult C. sterbai and I check any I have in auctions about an hour after they were boxed, if they're okay then they should be fine from then on. If the water is cloudy then I re-bag them in fresh and again, they're usually fine after that.
I think Ian has a trick whereby he gets the fish aggitated first then quickly switches them into fresh water but I've never tried that.

[apistomaster]

Thank you for your input.
I have been aware of this self-poisoning phenomenon with Corydoras sterbai but except the two incidents I described I have never had any problems transporting 50 to 100 juveniles of about 1-1/4 inches to shops within a couple hours away.

In the first incident with adults I actually went out of my way to panic them, make several water changes then do the final bagging and those were the fish I never ended up shipping.

This last time I did not do anything more than absolutely necessary to catch them and then I provided 14-15 fish with about the same amount of space I have been able to transport almost 100 of the typical selling sizes for retail shops. I had hoped not to alarm them much and allowed a lot of water and air for this small number of fish. I used the standard 20 X20 or 22 X 22 inch single fish box; the standard type used for use when packing two styros in one larger cardboard box.
It seemed like I was being conservative enough but I was concerned and I told my friend I had reservations because these Corys are known to produce fatal toxins when alarmed in a confined space and would only ship them at his risk since I had held them a year and turned down a local sale after verifying with him that he definitely wanted these breeders.

The very mature and large specimens are touchy. I doubt whether adding activated carbon would have made much difference with a 48 hour transit time. There hasn't been any research done that I know of which has identified the toxin. Carbon can absorb some toxins but some are effective at minute doses so one needs to know what if anything exists which would neutralize it. It seems to be a neurotoxic substance and as a whole, neurotoxins are effective at low doses and are difficult to reverse. It would make an interesting research project to chemically identify and discover a neutralizer. It could be as simple as a fairly high dose of potassium permanganate, a strong oxidizer.
I have sent out over 160 plecos so far this year and have only had one DOA due to a punctured bag. In trial experiments with plecos shipped in breathable bags I finally had to release the test fish on day 7 because by then they were beginning to look skinny but they all survived. None of my experiences, not even my first C. sterbai problem quite prepared me for such a total wipe out and these were as nice and large C. sterbai breeders one could ever want. I used breathable bag liners but not as breathable bags. I allowed plenty of air for them. The first time I could chalk it up to not allowing enough water/air per fish and it only affected me and no one else. The idea was my friend could have, should have been able to raise enough young easily from a couple spawns to pay for them twice over in his market. Their prices quickly dropped in only a few years locally, from $14.99 each down to only $5.99 each. I will never bother with Corydoras sterbai again. They are just too risky.

I know when I had a fish shop I used to buy Corydoras in box lots which were usually 100 fish in the same size box. Sometimes they would all arrive dead, especially large specimens, but for the most part the majority of the shipments arrived fine but those that were dead often looked like they had been packed with full guts and released large amounts of waste. I fasted these Corydoras sterbai 2 days before I packed them to help keep their water clean.