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Hi, recently I see that I start to have problems in my fry of Corydoras, especialy in duplicareus, but also increasingly in sterbai. I hadn't problems of this sort before, or at least not so visible, probably because I didn't rear such a large number of fry. Now I have hundreds of fry and I see that the longer the fry stay on the glass bottom, the higher is the probability that they lose barbels.

The remaining duplicareus in tanks are almost all without barbels, the slowest growing sterbai also show these signs. Is there any possibility, how to stimulate the regeneration of barbels? I don't want to sell such fish.

I think the fry get infection from the bacterial slim on the bottom, so I now clean the bottom during every water change (every 5th day), but it seems that it doesn't help. Adding sand into the tanks is unimaginable for me; I can't maintain the tank properly.

cartouche wrote:Hi, recently I see that I start to have problems in my fry of Corydoras, especialy in duplicareus, but also increasingly in sterbai. I hadn't problems of this sort before, or at least not so visible, probably because I didn't rear such a large number of fry. Now I have hundreds of fry and I see that the longer the fry stay on the glass bottom, the higher is the probability that they lose barbels.

Hello. I raise all of my fry in bare-bottomed tanks and never experience any barbel damage. I do scrub the bottoms of my tanks every 2 or 3 days with a paint brush, which works quite nicely as I can even use it with wigglers and not hurt a one.

The remaining duplicareus in tanks are almost all without barbels, the slowest growing sterbai also show these signs. Is there any possibility, how to stimulate the regeneration of barbels? I don't want to sell such fish.

If the fry are very young, there is a high probability that regeneration will take place. The older the fry, the less likely this is to occur.

I think the fry get infection from the bacterial slim on the bottom, so I now clean the bottom during every water change (every 5th day), but it seems that it doesn't help. Adding sand into the tanks is unimaginable for me; I can't maintain the tank properly.

OK. I lied when I said all of my tanks were bare. I did, 2 days ago, put some play sand in a 10 G. tank of young C. weitzmani. I would like to take this opportunity to publicly apologize to ever Cory I have ever kept in a bare bottomed tank. The play sand completely changed the look and activity of the fish. I have no plans to put sand in all 96 tanks, but I can promise you that many more will get such treatment. It does make a difference. - Frank

I use sand in all my Corydoras tanks and never experience these barbel issues (only once with C. concolor, but that was due to bad waterquality I think. They gos much better after I changed the filter).

In the past I used bare bottoms for fry, but found that the pelvic fins of some species and the barbels also was damaged/under developed. This problem has stopped after I started using sand.

kim m wrote:I use sand in all my Corydoras tanks and never experience these barbel issues (only once with C. concolor, but that was due to bad waterquality I think. They gos much better after I changed the filter).

In the past I used bare bottoms for fry, but found that the pelvic fins of some species and the barbels also was damaged/under developed. This problem has stopped after I started using sand.

Hmm, using sand? I tried it once - and I would never repeated it again. It was a nightmare. The fry can't be seen on it, food falls among the sand grains...

cartouche wrote:

kim m wrote:I use sand in all my Corydoras tanks and never experience these barbel issues (only once with C. concolor, but that was due to bad waterquality I think. They gos much better after I changed the filter).

In the past I used bare bottoms for fry, but found that the pelvic fins of some species and the barbels also was damaged/under developed. This problem has stopped after I started using sand.

Hmm, using sand? I tried it once - and I would never repeated it again. It was a nightmare. The fry can't be seen on it, food falls among the sand grains...

Then you'll probably be horrified when I tell you about my experiments :

45 litre tank with HMF filtering and sand bottom...thick layer of oak-leaves and lots of javamoss.
All eggs laid during a whole week is dropped into the tank. No anti-fungal chemicals are used. A week later I start feeding microworms. Later I use decapsulatus artemia eggs and crushed pellets.
It can be up to a couple of weeks or even longer before I even see a fry in there. After a month they are everywhere, several species in the same tank.
They fry grow faster in this setup than others I've tried. Also, the number of fry with deformities are lower than usual.
I do 2-3 weekly 50% waterchanges in thiese tanks.

cartouche,

Just to put you in the picture regarding sand, which you probably know already, but it is more than likely that 90% of Cory species live over a sandy substrate. Some live in areas that are heavy in silt or even clay. However there are none living over glass. This will be the same for new hatchlings and developing fry. So if you are using plain glass bottomed tanks, as Frank has already suggested you need to make sure the the bacterial slime is cleaned of the base regularly. It is the abrasion caused by the continuos rubbing against the glass and believe it or not is quite abrasive especially to the barbels of tiny fish, which causes inflammation to the barbels. This added to the constant contact with the bacterial slime, which is creating the reduction of the fry's barbels.

For the record I never use plain bottomed tanks.

Ian

I had a similar epiphany to Frank with respect to sand on the bottom of tanks.

http://www.planetcatfish.com/forum/view ... light=c121

Coryman wrote:cartouche,

Just to put you in the picture regarding sand, which you probably know already, but it is more than likely that 90% of Cory species live over a sandy substrate. Some live in areas that are heavy in silt or even clay. However there are none living over glass. This will be the same for new hatchlings and developing fry. So if you are using plain glass bottomed tanks, as Frank has already suggested you need to make sure the the bacterial slime is cleaned of the base regularly. It is the abrasion caused by the continuos rubbing against the glass and believe it or not is quite abrasive especially to the barbels of tiny fish, which causes inflammation to the barbels. This added to the constant contact with the bacterial slime, which is creating the reduction of the fry's barbels.

For the record I never use plain bottomed tanks.

Ian

Well, but my adult fish virtually never lose barbels, despite living on the glass bottom for many years. Maybe a high level of nitrates can also contribute to it (nitrites are no problem), but since I observe it even in tanks with a relatively low concentration of fry, it may not be the main cause. It really appears only after the fish are on the glass bottom for a long time.

Maybe I should furnish the tanks with 50% bare bottom, 50% sand bottom.