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One of my panda corys has taken to hanging out at the surface of the water. At first I thought it was just getting a "drink" of oxygen, but would stay there for long moments.

It started after I fed some frozen bloodworms, some of which remained floating at the top. The pandas actually realized what was going on and went to the surface to feast on what they could find.

Is this normal behavior, for this particular panda to keep searching the top day after day? I don't feed bloodworms every day (more like every 3 or 4 days). The only fish I have in a 10g are panda and pygmy corys, and the water quality is consistent (Ammonia=0, Nitrites<0.3ml). This panda doesn't otherwise seem to be ill or anything, but it makes me a bit worried.

Okay, this font is really hard to read. I'll make sure to change it.
Last edited by CancerMan at 03-Sep-2005 12:05

Last edited by CancerMan at 03-Sep-2005 12:07

Hola and welcome to FishProfiles.com.

How old is the tank? You have nitrites, which is unusual if the tank is more than a month old... It means the tank is still cycling. In a completely cycled tank, both ammonia and nitrites will be undetectable in water tests.

Nitrites are toxic because they reduce the amount of oxygen in the fish's blood. This would explain why your fish is gassping for air at the surface. Panda corys also tend to be very sensitive to any water quality issues, which is why none of your other fish are exhibiting the behavior.

How old is the tank? What other fish are in it?

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I'm not your neighbor, you Bakersfield trash.

I recently got panda cory's about a month ago and had a nitrite spike. Do you have any plants or an airstone that would help oxygenate the water since nitrite reduces the amount of oxygen in the blood those might help.

"A noble spirit embiggens the smallest man" Simpsons

I've had the tank for longer than a month. It contains 5 pandas and 6 pygmys. None of the other pandas, nor the pygmys exhibit this behavior.

I have that tetratest water test kit, the one you add the liquid drops to a vial. When I mentioned my nitrite levels, I was reading the little color card that came with the kit, which only has "< 0.3 mg/l" So maybe I don't have nitrites, the card only indicates I have less than 0.3

I do have air stones that oxygenate the water

I really hope this panda is just looking for bloodworms...

Last edited by CancerMan at 03-Sep-2005 20:41

Last edited by CancerMan at 03-Sep-2005 20:42

I've noticed that oftentimes when Corydoras hang at the surface for longer than usual to take their air gulps, they are ill and sometimes die soon after the behavior starts. On the other hand, it could just be your fish's preferred method for getting air. I have a Corydoras guapore that started acting like this soon after I bought it. He swims slowly up to the surface for air, then loiters there and takes multiple gulps over one or two seconds. He’ll then swim slowly back down. None of my other cories have exhibited this behavior, so he couldn’t have learned it from them. I doubt that my fish is sick either, because I’ve had him since spring of this year. There’s the possibility that your fish is just different.

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And when he gets to Heaven, to Saint Peter he will tell: "One more Marine reporting, Sir! I've served my time in Hell."

To be safe you should go and get the water tested at the lfs to check the accuarcy of your test. You should have NO nitrites at all if the tank is cycled properly. To dilute the nitrites try doing a water change or 2.

"A noble spirit embiggens the smallest man" Simpsons

Watch carefully to see if he heads back to the substrate.

If he does, and his forays to the surface just happen to be temporary, then you're OK.

If he stays at the surface despite efforts to descend, then you've got a problem. And one that could prove terminal.

The problem here is that Corydoras are normally negatively bouyant. That is, they're normally slightly heavier than the surrounding water. All the better to sink to the substrate. This means that they have to exert effort to reach the surface to take in atmospheric air, which is necessary because these fishes have evolved to respire via a specially adapted intestinal lining.

However, if for some reason they become positively bouyant (usually trapped gases of one sort or another) and they have difficulty eliminating the trapped gases, then they can find themselve stranded at the surface. If an affected fish is swimming the right way up, then this is usually a good sign, but even so, be prepared for matters to worsen. If an affected fish is stuck at the surface upside down, then it's serious.

As far as I can tell, the only safe way of dealing with this trapped gas problem would be if someone could devise a decompression chamber. I know what some people will be thinking at this point, so allow me to explain.

If the fish is subject to steadily increasing pressure, then the gas bubbles will become smaller and smaller as the surrounding ambient pressure increases. The fish adjusts to the steadily increasing pressure as it would if diving into deeper water of its own volition. Any gas bubbles present, however, are compressed, and may even dissolve. Now of course, the trick is to decompress the fish so that the gas bubbles don't return. The "journey up" as it were, will be a lot slower than the one down. Anyone who has engaged in scuba diving below about 30 feet will be aware of the phenomenon I am referring to.

So, one needs a vessel capable of withstanding some pressure, a means of applying that pressure, and a means of releasing that pressure in a controlled fashion. Sadly, no-one has produced or marketed a device of this kind for aquarium therapeutic use to my knowledge. Consequently, any home-made device to reproduce the same results would be highly experimental. However, compression at a moderate rate, followed by a slower decompression, could theoretically alleviate gas bubble problems in a wide variety of fishes, not just Corydoras.

Indeed, it is entirely possible that some of our fishes may suffer from gas bubble problems, because they are kept in aquaria whose depth is too shallow to exercise their depth control systems adequately. It would be interesting to see what depth would be occupied by, for example, Lemon Tetras in a really deep aquarium - in a home aquarium they rarely encounter depths of less than 18 inches, while in the wild, their home waters could easily be several feet deep. Similar provisos apply to Corydoras, although Pandas are usually shallow-water dwellers in the wild, and have been known to suffer if kept in too deep an aquarium (I recall Jessnick had this problem).

Hope this somewhat rambling discourse is of use to you!



Panda Catfish fan and keeper/breeder since Christmas 2002