Hastatus Dwarf Cory Conundrum!

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longliveglam

Aquarium Advice Apprentice
Joined
Sep 21, 2008
Messages
28
We just added six fish to our three fish family, including two hastatus dwarf cory.

We thought they were dead this morning because they were sort of motionlessly lying in a corner of the tank together (the tank is 20 gallons). Originally when we brought them home, they went to the bottom but started swimming up high within minutes, and basically acted like the other fish.

Lately, though, they've been just lying there. We only know they're not dead because when we prod the glass, they move, or their gills move. But they're not very life-like at the moment and we're wondering if this is a sign that there is something wrong with them, or whether or not this is just something that they do as a species.

Thanks for the help.
 
Apologies for sounding like an idiot, but what do you mean by water perimeters? It's a 20 gallon tank. Do you mean width by length (the tank)?
 
We tested ammonia and nitrate right before we put them in, and it's all clear. There shouldn't be anything wrong.

ALSO: If this IS what they're supposed to be doing, just lying there, how will they get food? Will flakes suffice? They don't need special things that get to the bottom, do they?
 
Are they sitting upright on the bottom (ie on their belly, which is fine) or are they lying over on their sides (bad)? Corydoras catfish are generally bottom dwellers, and spend much of their time sitting or poking around the bottom. They will likely not come to the surface to feed or spend much time swimming around in the water column. Some sinking pellets would be beneficial to make sure they get enough to eat besides the occasional flake that makes it down there.

As for your water parameters, what do you mean by "clear"? It's much better if you post the actual values of the readings you got just to be sure.
 
They are sitting upright at the bottom of the tank, but contrary to what you said they're not poking around but rather... laying there.

With the water parameters, we compared both to the charts they came with and both matched the colours that indicate...no ammonia/nitrite AKA perfection. XD

Are the sinking pellets needed? If so, how many should we put in for the two? We also have a bottom dweller (upside down cat), but he seems to move around enough to get the flakes that sink. This is what concerns us about our cory fish. They hardly ever move, so they can't compete for food. How can we make sure they get enough to eat?

(Thank you, by the way. This relieved us a lot.)
 
Contrary to what a lot of people say, nitrates can have a harmful effect as well. You really need to test for this. In the beginning of my fish keeping career I had a bunch of platys who all stayed at the bottom of the tank and showed very little movement. They all died hours later. I found out later that it was due to high nitrates.

Prior to this everyone assured me that nitrates weren't dangerous and that as long as the tank was cycled everything would be fine.

I urge you to test for nitrates in your tank.
 
Yup... test for nitrates and if they're above 20ppm do a 50% PWC.

The other thing that could have happened is that they were not acclimated properly... how did you introduce them to the tank?

You'll probably need sinking wafers/pellets as they're bottom feeders (I have 2 cory cats and they get half of a small algae wafer to share).
 
My friend and I are both unsure as to whether the test for nitrites is also for nitrates; if it's just for nitrites we'll be sure to look into nitrate tests as well.

We float the bags for twenty minutes before putting them in the tank. The aquarium staff advised us to add some of our aquarium water to the bags, but my dad (experienced in fishkeeping) said it was fine just to float them so the temperatures leveled out.

Are nitrates particularly harmful to platys, though? The people who advised you maybe owned fish that weren't as affected.
 
The other thing to consider is whether or not the sinking pellets are surviving long enough for them to get to them: I've started using sinking algae wafers for an apple snail, and my 2 platties and 3 adult guppies pounce on them. I see the neons and fry there in the frenzy as well.

The snail wouldn't come close to fish, let alone get at the wafers.
 
No- nitrIte tests are different from nitrAte tests. NitrAtes are harmful to every fish over 20ppm or so.

Please read up on acclimation:

http://www.aquariumadvice.com/articles/articles/2/1/Acclimation/Page1.html

The aquarium staff are generally not very well trained- in this case they were correct (sort of). Temperature is not the only difference your new fish will encounter in changing tanks...
 
Generally dwarf cories like your hastatus are more active than their larger cousins. Like all cories they are happier in a school. It could be that the water parameters are off, they are intimidated by one or more of the other inhabitants, or that there are too few of them for them to feel secure.
 
Regarding the pellets, Johnny, I see what you mean; I have a feeling our upside down cat would get to it before the corys would with the way they're behaving.

We'll be sure to be more gradual with our acclimation in the future, as well; for now I skimmed, but I did get the basic idea—thanks. :)

Aside from the nitrates, our tank is fine. It would make a lot of sense if our dwarf corys are intimidated seeing as we have two guppies now (German yellow and red cobra), two harlequin rasbora (who are very well behaved), an upside down cat, and a male cherry barb who parades around the tank like a psycho dictator who is often chasing everyone else down. :\ (I'm unsure as to whether this is typical cherry barb behaviour, if he's restless from bad parameters, or if he's just... ridiculous.) Keeping this in mind, we'll consider getting more hastatus dwarf cory sometime in the future.
 
my tank (37gallon) appears to be cycled (NH4=0, NO2=0, NO3-0-5ppm) after approx 30 days and I added 3 cory's (salt&pepper but less than an inch in length) and they are doing pretty much the same thing. I see them swim a little every now and then, but for the most part they're wall flowers....
 
For a 20 gallon with the room to accomodate them, I would have at least 8 or 10 hastatus. They are a very shy fish and can be very insecure around larger fish, especially when there are only small numbers of the hastatus. For a hastatus that means almost everyone except neons and heterandria formosa are big enough to scare them.
 
I haven't seen a test that was valid for both nitrite and nitrate. They are chemically different and interact with your fish very differently, so it wouldn't make sense to me to market a combined test. It would give you false readings pretty much by definition wouldn't it?

The reason for adding tank water to the bag is to allow them to adjust to differences in pH as well as temperature. I've never personally seen adverse effects from temperature-only acclimation like that, but I tend to keep much hardier species than you all do. Some tropical fish may be more sensitive to it. If you intend to keep doind that I would recommend at least once testing the store's water from the bag to make sure there isn't a big difference in pH. If the water is similar then you should be fine.

It's been a week since you posted this thread. Are the fish behaving any differently?
 
I agree with OldMan. I have Hastatus Cories and found them to be really shy. :) I have Apistos with mine, but the Cories do alot of hiding (though they do move around in my plants). They swim mid-water and don't spend as much time on the bottom as my larger Cories in a different tank.

I would definitely get atleast 6 more, if not 8 more to make them feel more secure. And be sure to have some hiding spots, whether they be plants or some other decorations.
 
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