Corydora death.

[Hipuks]

Life has a way of pimp slapping you in the face when you think everything is going perfect...Allow me to explain. So yesterday I wake up at around 7PM ( yeah I know, to say I'm a night owl would be an understatement) and of course, first thing I do when I go downstairs is check my tanks. And there it was, on my bronze cories, his grotesque white body floating lazily in the current. He was eyeless and finless, obviously, his fellow tank mates had used him as a snack after his death, my beloved cory, reduced to the fish equivalent of a bag of Doritos. So I immediately take him out of the tank with the net, and bury in one of my grandma's flowerpots, why do I do that? I don't know, it seems a little more dignified than flushing him down the toilet. I check the water, to see if something was wrong, and I have 0 ammonia and 10 nitrate. Pretty standard reading.
 
Then I think, maybe he just died of natural causes, maybe you didn't eff it up this time. And then I look at my other cories, I had 6 in total, of the surviving 5, two look completely fine, but the other three, I noticed their barbels were too short. One of them had a normal barbel on one side but no barbel on the other side. I think, how did this happen? The only answer I have come up with, involves me being a dumbass of course. Here's the thing, like a week or two ago, I decided my 20H needed something new, so in front of the driftwood, I put some white Kordon Wonder Rock. I also thought since this gravel was going to be smaller than the one I had, the wafers wouldn't get stuck in places the cories wouldn't be able to reach. Now I think that maybe this new rock is too rough for them, and that's why they been losing their barbels. It's just an idea, you guys  know way more than me and perhaps can tell me what happened.


Here's a pic of the Kordon Wonder Rock:




And here's a pic of the area where I put the rock.





Could that have caused them to lose their barbels? Now that I have 5 cories left, will they be OK like that or should I add one or 2 more? Are the cories with short or no barbels doomed? Thank you for answers.

[Gopi]

That gravel does seem a little large for them. I think they would appreciate an overall change to a smaller gravel closer in size to the Kordon or smaller...and smooth.

Wait at least 2 weeks before adding fish after a death (some will even say a month) and the count restarts if there is another death or illness. Also, make sure you QT any new cories you get.

[Markalot]

It would be nice to know your water parameters tested using the liquid test kits, like the API freshwater kit.

When fish start dieing the first thing to look for is bad water quality, then disease, then after that's out of the way other things can be looked at.

http://www.novalek.com/kordon/wonder_rock/index.htm

I don't think wonder rock is the problem.  Perhaps something failed in the tank, the biological filter was disturbed, some contaminant got into the tank, etc.

[kcgirl81]

Also, don't add any more cories until you've figured out if there is a problem in your tank (whether with water or with gravel size, whatever). They'll be fine with just five for the time being.

[Hipuks]

The water parameters, tested after the fish's death are 0 ammonia, 10 nitrate, and a PH of 7.6

What do you guys think of using sand in the tank? Would that be good or bad for the cories?

[secorneli]

The cories would like the sand.  They like to root through it and it would be easier on their barbels.  I have half gravel and half sand in my 65 gallon - gravel in the back and sand in the front.  I used play sand from Home Depot; very cheap but you have to rinse it thoroughly or it will turn the water cloudy. 

[Hipuks]

Yeah, that's what I was thinking, playsand from Home Depot. The only thing that worries me is that plants won't be able to root very good, maybe if I use like 2 inches of gravel in the bottom and then sand on top? Also, can you gravel vac normally in a tank with sand substrate?

[Markalot]

I find that all the plants I grow love the sand, no rooting problems at all.

[secorneli]

In this link you will find all the info you ever wanted to know about cleaning gravel and sand substrates:

http://www.badmanstropicalfish.com/forum/index.php/topic,10977.0.html

[Hoots]

My plants are great in around 3 inches of play sand from home depot.  If you were to add sand to your rocks now, it would eventually work it's way down to the bottom. 

[Hipuks]

Well then, I've been convinced. I'll switch to sand.  Though for changing from gravel to sand, I have no other choice but to tear the tank down do I? It'll be worth it anyway. Thanks for all the help peeps, I don't know what I'd do without you.