Panda Cory's dying one by one...

[keights]

Tank
37 Gallon. 1x50g Aquaclear HOB and 1x30g Aquarclear HOB. 50g HOB has been on for over a year, 30g in last month (previous 20g backup filter quit).
Tank Mates:
6 Harlequin Raspboras, 8 neons, + Panda Corys.
Water parameters
Zero ammonia, zero nitrites, every few days nitrates are between 5ppm and 10ppm and I do a small water change (rather than 25% once per week, I am doing small changes 2-3 times per week equal to TOTAL about 30% per week). Temp. approximately 73 degrees.
Issue:
Panda Cory’s dying one by one.
Details:
Feb 19th added 8 pandas. Feb 22nd lost one. I saw one zipping all over the tank and when I glanced in an hour or so later one was dead – not sure if it was the same one. Feb 27th added three more pandas for a total of 10. March 7th & 8th – lost one more each day. Down to 8 (a total of three deceased). March 14th – one more deceased. March 15th – saw one that was healthy last week (despite missing an eye – I think he may have been that way when I got him?) was looking very thin and had stopped moving around much and by this morning he was dead as well. Total five deceased, six living.

I have observed that one cory is exceptionally pale and I keep expecting him die but he seems fine, and active. I have one cory who is 75% bigger than all the rest and I am almost wondering if this one is bullying the other fish?
I have observed that the neons are eating the sinking pellets that are meant for the pandas and that the raspboras have taken to ignoring their flake food in favour of hanging out near the bottom of the tank – they wait for the other fish to bite into the pellets and grab pieces as they break loose and float upwards. So, to compensate, I am feeding less flake food and more pellots and breaking the pellots in ½ before sinking them to give all the fish a better chance at finding them.

I am at a loss as to what to do. I love these little cory’s but I certainly don’t want to get more and have them die too….plus they are pretty hard to find around here.

Any ideas? Suggestions?

Now the pale one is not moving...

 

[Ilikefishes]

Pictures please?

 

[7Enigma]

If it's a food-related issue (ie they are starving) and not a disease/aggression I would recommend crushing some of the sinking pellets. Corydoras are filter feeders in proper substrate (sand/fine particles) and can find food that other fish can't. Another recommendation would be to add some more cover in the tank as they tend to be shy and won't eat (especially if there are aggressive fish around).

Please post a pic of the tank and some closeups of the cory's if you can.

 

[mfdrookie516]

what kind of substrate do you have? if its sharp, it can cause them to lose their barbells which will cause them not to eat...

 

[keights]

7ENIGMA - Thanks for the advice. I put a few more small silk plants on the bottom of the tank for some more cover and crushed their food last night so the larger fish couldn't get at it. I had only four cory's left alive when I got home last night, they were all moving around this morning, and I am praying they are alive and well when I get home tonight. If this is all it is I'll be happy it's solved but upset that I didn't figure it out earlier *sigh*

 

[keights]

Update: Last night I still had all the fish I had the night before, and this morning. I'm hoping this trend continues.

 

[mattrox]

I had this happen to my pandas too a few years ago. It is a wasting disease. Mine stopped eating, my feeling is that it was internal paracites. By the time they stop eating it is almost certainly too late to save them.

If you have a qt, I'd remove them to it asap. If the ones you have left are eating, try a medicated food for internal paracites. Or if you can get 'Metro' I forget what its proper name is, you can crush up the tablets and treat the water.

 

[mattrox]

http://www.aquariumadvice.com/forums/f17/internal-parasites-110575.html

Here is a link with the info on treating with metro.

 

[7Enigma]

Update? Hopefully everything is going good?

 

[keights]

It's been over a week and I still have the four remaining cory's. I'm still not entirely sure what the issue is but the health of them is as follows: One looking very good - he is grown so much I call him the monster fish. Two have started to grow and are about double the size they were when I got them. The fourth has not grown at all but he is swimming around, active, and hanging with the other cory's.
For now, I'm just going to keep doing what I'm doing and keep my fingers crossed.
Thanks for all the advice - I think the feeding may have been a big part of the issue, and part of it that there was still some gravel substrate (I'd been slowly transitioning to sand - now complete).

 

[mattrox]

I'd treat for internal paracites, especially if they are eating now. If you can find medicated food, I'd try.

 

[7Enigma]

I'd treat for internal paracites, especially if they are eating now. If you can find medicated food, I'd try.

Agreed. Better to rule the possibility out than to hope it's fixed (we've all done that and normally it ends badly a couple weeks/months down the road). I had little luck with medicated foods (none of my fish ate them) and I think they stopped carrying Gel-tek brand here in the US which was the only one I knew of that was accepted by most fish (they might still in AU). If you can find that try it. Otherwise search for posts I made about a dog dewormer that I used sucessfully twice now. You can probably find a similar product (active ingredient fenbendazole I believe) locally and be sure you are not dealing with IP's.

HTH

 

[mattrox]

In Australia you need to get a vet's prescription for metro, and it was not cheap!!! I needed for discus a few years back. My advice to anyone with fish getting skinny, wasting away or white stringy poo it to QT them in a small tank get metro, boost the temp and treat. Too expensive to treat in a big tank. And if the effected fish are removed from the main tank there is less chance for the disease to spread. I swear to this day that the pandas introduced the disease and got my Discus sick.

 

[7Enigma]

In Australia you need to get a vet's prescription for metro, and it was not cheap!!! I needed for discus a few years back. My advice to anyone with fish getting skinny, wasting away or white stringy poo it to QT them in a small tank get metro, boost the temp and treat. Too expensive to treat in a big tank. And if the effected fish are removed from the main tank there is less chance for the disease to spread. I swear to this day that the pandas introduced the disease and got my Discus sick.

Same way here in the US for most straight medications. Back when I was interested in treating my dwarf puffer flubenol was still available in the US. It was the best parasite treatment on the market as it was extremely effective just dosed into the water (didn't need to be in food/etc.). There was 2-3 other ones that I tried to get as well before finding this dog dewormer on recommendation by someone in a forum. Same medication that you would need a prescription to buy but available OTC in this particular form (note they are not the same medication, just using it as an example).