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My bronze corydoras is swimming funny. I have been keeping corydoras for about three years and I have never had this problem before. I'm wondering if this is natural or it is a problem.

Temerature range: 75 F
Ammonia level: 0
Water change frequency: Once a week

Tank set up
Size: 10 gallons
Substrate: Gravel
Filtration: Penguin Mini Power Filter
Furnishings: Silk aquarium plants and a rock cave - both designed for aquariums.
Other tank mates: One peppered corydoras catfish, one otocinclus, five neon tetras
How long has it been set-up?: Since early June

Symptoms/Problem description

He is swimming about two inches above the gravel. He is eating fine, but doesn't seem to be growing. He has been this way ever since I got him.

Redfish, when a cory starts to "swim funny" and is hovering over a gravel substrate, the problem is usually the substrate itself.
The two most likely things to have happened are these:
1. either your cory has eaten some spoiled food that he found while rummaging in the large crevasses of the gravel, or
2. some gravel was rearranged by the cory's efforts, and a bubble of toxic gas has come up and hit him in the face.

This kind of thing happens all the time to Corydoras, when they are kept on gravel substrates. The swimming funny is caused by disorientation and confusion. He may be poisoned fatally or he may throw it off. It depends how squarely the gas hit him. If he has eaten old and spoiled food, he may be suffering from disruption of the balance of gasses in the intestines, which is very painful as you can imagine, and may prove fatal as well.

This is what I suggest.
Immediately: try feeding some freeze-dried Daphnia to clear out the fish's system. This may work to right the balance of intestinal gas. Change some of the water, let's say 20%, just in case residual toxins are floating around.

Short-term: change your gravel substrate to a layer of fine, smooth-grained sand and spread this to no more than ¾" (2 cm, 20 mm) deep. Children's playsand (for sand boxes) that has been washed, rinsed, and dried is cheaply available at places like Lowe's. Expensive bagged sands like Tahitian Moon Black Sand (CaribSea) are very nice, and for a 10 Gallon tank you would only need about ¼ of a bag, or a little more. It's worth it.

Near-term: exchange the peppered cory for two more bronze corys or, if the bronze dies, get two more peppered. A group of one kind is better than one of each.

The five neons and one oto are good choices, and with the three corys (of one species) this should end up being a nice little tank.
Good luck.


ps:
You've been keeping bronze corys for three years, but this 10 G tank has been set up since June.
Questions: How long have you had the cory in question?
Was the gravel new when you added it to this tank?
Or did you use old gravel from a previous tank?
How deep is the gravel, and what size gravel (in mm)?
How much water do you change at a time?
Do you vacuum (siphon debris from) the gravel at each water change?

deb wrote:Expensive bagged sands like Tahitian Moon Black Sand (CaribSea) are very nice, and for a 10 Gallon tank you would only need about ¼ of a bag, or a little more. It's worth it.

Won't Tahitian Moon Black Sand raise the pH too high for corys? I have thought of using it myself but the pH factor put me off, what do you think?

Daragh

I don't know that TMBS will alter the pH in any way. It is an inert synthetic material, similar to volcanic glass. Think of it as rounded-off grains of obsidian.
It's not like white marine sand, which does tend to keep the pH up a little.

What makes you think it will alter pH?

I use it in a set-up with all catfish, mostly corys, and the pH is just about 7.0. My tapwater is about 7.8, with a low hardness of 3-4 degrees.

Deborah

Thanks. I'll try to get some play sand.

We just moved here earlier this year. I had fish before that when we lived somewhere else.

How long have you had the cory in question?
- Since early June, a few days after I set up the aquarium.

Was the gravel new when you added it to this tank?
- Yes, and I rinsed it thoroughly before putting it in.

How deep is the gravel, and what size gravel (in mm)?
- It is about 1/2-3/4 deep and about 2-3 mm.

How much water do you change at a time?
- 20%

Do you vacuum (siphon debris from) the gravel at each water change?
- Yes.

Would I be able to use my gravel vacuum on the sand? And could I find freeze-dried Daphnia at PetSmart or a local pet shop?
Thanks again.

It sounds like you set up the aquarium and then added fish, without letting the tank cycle. Is that right? Or did you use a biowheel from a cycled tank? Or some other biomedia from a mature tank?

If you did not, you may still be cycling, and perhaps your nitrites are spiking. Corys are very sensitive to nitrites, and may develop nitrite poisoning if exposed to them, so please check your nitrites with a test. They should be 0 (zero) but I am aware that there is a test kit whose lowest reading is not 0, and you may be using that one.

Your bioload isn't heavy for a 10 gallon, but in the absence of any live plants, water changes are the only way to export ammonia by-products until your good bacteria build up. You might want to change 20% twice a week, until you are certain you have cycled.

The problem with your cory could have to do with nitrite sensitivity. It's difficult to say. Your gravel isn't that deep or that old. There could be spoiled food in it, but I doubt the gas pockets have had a chance to build up after this short time - not if you are siphoning. However, the possibility is there and we don't really know.

So, let's say you follow the advice in the first post, adding an extra w/c and see how it goes. Do the nitrite test, and if you are okay there, perhaps everything will be okay. Effect the change to sand as soon as you can. The Penguin Mini is a pretty good filter for a small tank, and it's rated for up to 20 gallons, so you should be okay. (I've used one on a 20 gallon tank, and it was fine.) Just make sure to rinse out that cartridge pretty good, since you change them every month or so. Don't rinse your silk plants, they are growing good bacteria, and don't rinse the other decorations, either. If you must rinse them, don't rinse them all in the same week. Use a rotation, and save your good bacteria.
(If I'm telling you stuff you already know, please excuse me.)

Cleaning sand could not be easier.
The debris sits on top. Simply hover the siphon over it. I never have problems with sand in the filter box, or getting into the siphon, but it can happen. Just collect it at the end and add it back to the tank. You'll soon develop a system that works. I myself use a turkey baster (kitchen syringe) for siphoning in my 10 gallon, and have complete control over what I remove and what remains.

Keep your filter intake about three inches above the substrate. I think you will find that the corys will dig right down to the glass, keeping your sand stirred and fresh.

deb wrote:I don't know that TMBS will alter the pH in any way. It is an inert synthetic material, similar to volcanic glass. Think of it as rounded-off grains of obsidian.
It's not like white marine sand, which does tend to keep the pH up a little.

What makes you think it will alter pH?

I use it in a set-up with all catfish, mostly corys, and the pH is just about 7.0. My tapwater is about 7.8, with a low hardness of 3-4 degrees.

Deborah

The only shop I could find here that sells it was a marine fish sepcialist and they told me it was made from ground coral and would raise pH over 8. I will research further, I would be delighted if I could use it safely.

...

5 minutes later, I found http://www.caribsea.com/pages/products/super_nat.html and you are right it does not affect the pH, unfortunately though the makers site says it is not suitable for soft bellied fish or burrowers, I guess that would include corys

Daragh, see this thread:
http://www.planetcatfish.com/forum/view ... ht=#106274
Read down to see CaribSea's repsonse to my email to them. I can only repeat that I've been using TMBS for years, I've examined it under magnification, handled it extensively, and have found no problem with it, but every benefit.
For instance, the slightly heavier particle is less inclined to come up in the siphon.
But you must decide for yourself.

Based on your experience and their reply, I think it is definitlely worth a try. Thanx for the information.


Daragh

I checked the nitrites, nitrates, ammonia and pH.

The nitrites are at 0 ppm.
The nitrates are at about 10-15 ppm.
The ammonia is still at 0 ppm.
The pH is at 8.0 ppm. I tested the tap water that I use and it is at 8.8 ppm pH or over.

I did not use a biowheel from a cycled tank.

When the fish does sit on the gravel, he acts like it bothers him. Is it possible that he just doesn't "like" the gravel?

I'll try to get some playsand next time we go to the store.
Thanks again

Redfish wrote:I checked the nitrites, nitrates, ammonia and pH.

The nitrites are at 0 ppm.
The nitrates are at about 10-15 ppm.
The ammonia is still at 0 ppm.
The pH is at 8.0 ppm. I tested the tap water that I use and it is at 8.8 ppm pH or over.

pH isn't a "ppm" measure, it is "units of pH", which is essentially the negative concentration of hydrogen ions in the water (so higher means less hydrogen ions). It is a logarithmic scale, so 1 more pH unit is 10 times less hydrogen ions.

Your measurements are "sensible" and indicate a cycled tank, so that's fine.
[quote

I did not use a biowheel from a cycled tank.

When the fish does sit on the gravel, he acts like it bothers him. Is it possible that he just doesn't "like" the gravel?

[/quote]Probably more the "stuff in the gravel" rather than the gravel itself, like Deb said.

I'll try to get some playsand next time we go to the store.
Thanks again

I use playsand in most of my tanks, and I'm happy with that.

--
Mats

When buying play sand grit size is very important. I recently bought a bag of labeled "Playsand" at a "big box" home improvement center. The grit was so fine as to be almost dust. This is Silica and not a healthy thing to be breathing when working with the dry material. 30 grit is the smallest grit size I would consider and it still contains a great deal of dust which must be rinsed out. I would strongly suggest the use of a good respirator when working with any of the silica sands.

Gordon wrote:

The grit was so fine as to be almost dust. This is Silica and not a healthy thing to be breathing ...

I'm surprised this was the case. Children's playsand, as used for sand boxes and as dressing for swings areas, is prepared to be free of this kind of dust. It is washed, rinsed, and dried before it's put in the bag.
Since children will be in close contact with the grains, they are rounded and not sharp, and of a particle size that brushes off easily.
Usually, they are not treated with any chemical of any kind, even mold-suppressing chemicals.

For those who want to use play sand, the best thing to do is to go to Lowe's (or a similar well-known home improvement center) and inspect the different playsands available. Read the bags for preparation methods and ingredient lists. Ask, no demand, to see samples of their children's playsand. They will not argue with you. Usually there's an open bag, anyway. Examine the grit size. Take a sample home and examine it under magnification to judge the grain size and to make sure the grains do not vary widely in size. Ideally, there should not be more than a 0.5 mm variation in grain sizes for a Corydoras set-up.

Deb
I was stunned by this situation and in fact it was a Lowes where I got the sand. The bag is very clearly labeled play sand and listed the various child related uses. I totally agree that when purchasing sand it is critical to make sure you are getting the appropriate material for use. Keep in mind though that even with a good washing there is still likely to be some residual dust that you will have to wash out yourself using the proper safe guards to prevent inhalation.

Gordon, I've got sand on the brain because we just had a really detailed discussion about it on corydorasworld (a dedicated Corydoras website http://www.corydorasworld.com/ ). It was generally decided that builder's sands might contain particles which varied too much in size, although some Europeans used sand-blasting sand, and didn't find it too harsh or too fine. In the UK, children's playsand was the overwhelming choice, and some purchased it from toy stores.
The subject of silica dust was brought up by me - in fact I started the topic. It seemed to be a non-issue in the UK, as far as children's "sandpit" sand, and I have to say when I went to Lowe's and sampled two suitable sands, I didn't see a dust problem.
However, not all sands are equal, as you point out so rightly, and all precautions need to be advised. Whether people choose to follow them is their decision.

Redfish, please let us know what sand you decide to get and how it goes. I am sure your corys do not "like" the gravel; they can't dig in it, they can't push it around easily, and they can't sift it and shoot it out through their gills. Food which should be within their reach ends up in the crevices where they can't get at it. A cory just can't have any fun on gravel. Seriously.