Extremely lethargic Cory, high nitrates   2/21/11
Hi!
<Hello Angela>
I wrote about a week ago on another issue, and never received a reply.
<?! We respond to all>
I'm hoping I didn't do anything wrong and my message was just overlooked!
<More likely some "computer glitch"... As the WWM "doorkeeper" ala LeGuin's Earthsea double trilogy, I see, post all>
As it is, that issue seems to have resolved itself for the most part. Now I'm dealing with something in my other tank, and I'm hoping for some insight from more experienced hobbyists than myself.
Tank: 14gal (functionally about 11-12gal with substrate and lowered water level), Aqueon filter that came with the "starter kit", temp steady at 75*F, fully cycled and has been set up since early December 2010. The pH runs pretty steady at around 8.
<For what species of Corydoras? This is too high... I'd mix in some water of lower pH... likely RO>
I always treat new water with Prime.
<Likely not necessary, but...>
Residents: 3 peppered Cory cats, 4 albino Cory cats, 2 juvenile mystery snails. The Corys are being quarantined here, their eventual home is a 55gal. I've had them for about 2 weeks.
Tank stats last night, with API test kit:
Ammonia: 0
NitrItes: 0
NitrAtes: over 80 (YIKES!!!)
<Needs to be addressed... Have you read here: http://wetwebmedia.com/FWSubWebIndex/fwnitrates.htm
and the linked files above?>
I performed my usual 30% water change, all I had time for, with plans to do another this morning.
This morning, I tested again:
Ammonia: 0
NitrItes: 0
Nitrates: over 40, close to 80 on test kit
Performed nearly 70% water change. Retested.
NitrAtes: less than 40, but close
<You need to do something in addition to simple dilution for NO3 here>
Now for the main problem: One of the albino Cory cats has been acting lethargic for the last couple of days, is not eating well, and after last night's water change floated belly-up for a few minutes despite all my attempts to match temperature, etc. with the new water. I was afraid we would lose him, but this morning he's better. Not great, since he's still spending most of his time resting on the bottom or swimming *very* slowly a few inches, but he's not floating. Everyone else in the tank, including a new baby balloon molly that hitchhiked home with the Corys, is acting and looking fine. Even the snails, which I thought would be the first indicators of poor water quality.
<Much more likely due to the vagaries of the water changes>
The only thing that changed recently is my husband taking over morning feedings for both tanks for the last week. I think he's been overfeeding this one, because I don't know what else would have caused such a large nitrAte spike in such a short time. There was a lot of "gunk" when I cleaned the tank, which isn't normal. I've taken over feeding again.
<Ah good>
Most of the reading I've done (Google is my friend, yes?) suggests that nitrAtes aren't *that* toxic over the short term, but these levels are pretty high and I've seen people mention again and again that Cory cats are "sensitive" fish. Could the nitrAtes spike alone be the cause of this little guy's problem?
<Mmm, yes>
If so, will continued water changes and much reduced feeding be enough to resolve it? If not, what else would cause an otherwise healthy-seeming fish to be lethargic and go off its food with no other sign of disease? I'm a loss on this one!
<Please read the above citations>
Thank you so much, I appreciate your willingness to help out newbies like myself with your amazing wealth of experience!
--Angela S.--
P.S. Is it just me, or are Cory cats just the funniest/cutest little fish ever?
<Are indeed comical, and faves. I keep them as well>
I was rolling with laughter after their first "feeding frenzy" over a shrimp pellet!! I'd buy a whole swarm of these guys if I could, but hubby says no room for more aquariums...
<Mmm, maybe... Bob Fenner>
Re: Extremely lethargic Cory, high nitrates    2/21/11
Thank you so much for the reply!
<Welcome Angela>
These are albino and peppered Corys (Corydoras aeneus and Corydoras paleatus). The lethargic one is an albino.
<The C. paleatus need much lower pH... the Albinos may be either C. aeneus or paleatus>
I'm in the middle of Kansas, so our water tends to run hard with a higher pH. Even the "expert" at the local store where I purchased these guys admitted it's hard to keep soft/acidic setups here without a LOT of work, <Not so much... easy to mix some tap w/ some RO... Read here:
http://wetwebmedia.com/FWSubWebIndex/fwhardness.htm
and the linked files above>
so I stuck with platies for our main fish. I was told that with careful acclimation the Corys would be ok, and honestly the other 6 look perfectly fine. I'll look into the RO water option, but if I can't get the pH down enough, should I find a new home for these fish?
<Maybe>
I'm not sure what I'd replace them with. (My 7yo son wanted a school of glass catfish, but there's no way we'd be able to keep them healthy. The Corys were a compromise, since most other catfish types he liked get too big.)
<There are many tools that can/will help you identify fishes, other aquatic life that enjoys your quality water>
I use the Prime instead of whatever brand dechlorinator came with my starter kit because we have copper piping in my house. I wanted to be extra careful to avoid getting copper in my aquariums and killing snails/fish.
<Real good>
The albino Cory is still alive, but he's pretty much the same as yesterday -- not swimming much, resting on a rock most of the time. I haven't seen him eat. I did one more water change last night, being careful to get the rest of the "gunk" out of the gravel. The nitrates are now reading between 10-20ppm, which is where the tank was before its regular water change the previous week. I'm going to be feeding lightly and testing the nitrates daily for the week, I think. I'll also be buying some more plants soon, so that will probably help a bit.
<Will help>
I read as much as I could about Corys/nitrates/etc. on WWM and the 'net in general before I posted, but I probably missed something. I'll go back and check out the links again. Thank you again for the response!
--Angela--
<Certainly welcome. BobF>

Cory playing dead 11/5/10
Hi Crew,
<Leanne>
Thanks for all the great work you do. I'm hoping you can help me again.
One of my four albino Corys has been behaving very oddly over the past few days.
He eats normally with the others each morning and swims around a bit but then spends much of the rest of the day lying on his back, appearing to be dead, until he is poked or touched by something. The first time I saw this I thought he was dead but when I went to net him out of the tank he immediately jumped up and started swimming around normally.
Each day since then I have noticed him doing the same thing but as soon as I put the net near him he rights himself and swims away. I saw him do the same thing when he was nudged slightly by another fish.
Is he really sick or is there some other explanation for this weird behaviour? The other three are behaving perfectly normally.
Thanks very much
Leanne
<Mmm, well, Corydoras can be/act like real clowns at times, but laying on their back or sides is not normal, healthy behavior. I'd look about for an anomaly water quality wise, or at least act proactively and institute a series of daily partial water changes and gravel vacuuming. Bob Fenner>

Itching Cory Catfish  7/10/10
Hello again,
<Hello Brian.>
You've been helpful in the past when I had questions about my first aquarium and some stocking advice for my second, so thank you.
<Cool.>
I did want to ask something about 6 new Panda Cory Catfish I added a couple weeks ago.
<A low to middling temperature fish; don't keep warmer than 25 C/75 F.>
They are the newest inhabitants to a ~4 month old cycled aquarium. They share a 46 gallon with a school of 9 Harlequin Rasboras, 6 Cherry Barbs, 3 Oto Catfish, and one last cycling Platy that's been tough to net out.
<OK. These should all do well at 24-25 C/75-77 F. Any warmer will stress the Platy, Otocinclus and Corydoras.>
Anyhow, as of yesterday morning I noticed one of the smaller Cory catfish do a few quick darning motions in the gravel on his side while scavenging for food. He only did it a couple times until the others joined him to start eating the pellets I dropped for them. I looked at the fish but didn't appear to have anything on his side, nor any discoloration (nothing I can see), and he's been actively swimming and searching for food as always. Then this afternoon, about an hour after they finished eating any dropped pellets, I saw the same behavior again; 2-3 quick darts in the gravel, and only in the gravel not on the decorations where I normally feed the catfish. It is a normal aquarium gravel, black, not sand nor a fine gravel that I've heard Cory catfish like to dig into.
<Hmm... "like" is perhaps not the right word to use here. Corydoras kept in tanks with gravel, especially sharp gravel, suffer from abrasions, in particular to their whiskers. You can instantly spot Corydoras kept in tanks with gravel because they have almost no whiskers, whereas those on Corydoras kept in tanks with smooth silica sand have whiskers that are very long, half an inch maybe. It's quite striking. While the missing whiskers aren't fatal, they do indicate that the fish are being damaged and vulnerable to secondary infections, which is a warning sign that all is not well.>
I still cant see anything wrong with him nor any of the other fish, including any of the other catfish. He still swims actively around and all over the decorations/plants as usual looking for food, so he doesn't appear sick.
<Flashing can be a variety of things, but the most common are these:
ammonia/nitrite above zero; Velvet; and Ick, in that order. Just because you can't see any other Velvet or Ick on the fish doesn't mean there isn't any in the system. Both these parasites go for the gills first.>
I guess I'm just curious if this is some kind of feeding behavior, like trying to scare up any buried food particles,
<No, Corydoras don't do this. When feeding on sand they plough their heads straight down, and spew the sand through their gills. It's fun to watch, and no-one who has kept Corydoras with sand EVER goes back the gravel. I'm not saying you can't keep them with gravel, but it's far, FAR inferior in terms of fun, both for you and the fish.>
or something of the sort and nothing to worry about, or if it's some sign of a disease that just isn't visible?
<Likely so.>
Water conditions for the past few weeks before adding the Cory catfish, and still...
pH ~7.5
ammonia 0ppm
nitrite 0 ppm
nitrate ~5ppm (weekly water changes)
<All fine.>
temp ~79F (extremely tough to keep any cooler in summer in Florida w/out a chiller)
<Will cause problems if it stays this warm. Do increase evaporation and try floating litre-sized blocks of ice in the aquarium.>
hardness ~200KH ~150GH normal for this area (but no problems with Platies and Cory catfish in a different tank for over 1 year)
<Indeed, water chemistry isn't a major problem for Corydoras, and Platies obviously prefer medium to very hard water.>
Thanks again,
Brian
<Cheers, Neale.>