PlanetCatfish.com

Hi all....

We are raising Corydoras Sterbai, using containers floating in an aquarium, then after they are a couple of weeks we put them into a tank w/cycled sponge.

We change the water at least 2x per day. But having fungus/slime form on some of the fry. Seems as though it is generated on the bottom of the container and once it attaches to the fry we can't get it off them.

Question is.... Has anyone used anything added to the water to prevent/retard the growth of this?
or has anyone had this problem?

Very disturbing that we have such a great breeding colony, great hatch rate but are having probs when they hit the 2 wk. mark.

please all ideas/thoughts welcome and appreciated

Try a litle Methylene blue, I use it in most of my Cory breeding tanks after the eggs have been laid.

Ian

Thanks for the quick reply
We also use that on the eggs... can you continue to use it? And at what ratio?

Hi!

I use to use Methylen blue in the past but after several bad experiment I decided not to use it anymore. Instead now I put the eggs that I collected inside a nursery filled with some Ceratophylum and place the eggs close to the surface, the whole thing being in the main tank. Since then I never had any problem with fungus.

Cheers
Yann

I don't really have any problems with Methylene Blue but I never use it at the full recomended strength, usually at about half strength 1 drop per 2 Gal (9 ltr aprox)

There is another natural control for fungus and that is a little fresh water shrimp called Acileus (Not sure about the spellling) these are often caught with Daphnia, one placed on a container with eggs will help protect them as theyfeed on the fungus spores.

Ian

Hello,

I have sometimes similar problems of "slime" in growing tanks. A very tnin layer of slime attaches itself to the sides and bottom of the container and sometimes seem to "attack" the fry which look glued in slime. Adding snails and java moss helps. Changing fry to a cleaned container also. I guess this is due a bacterial proliferation because of uneaten food (or microxorm culture medium)

Hope this helps.

Charly

I'm using a method invented by Werner Seuss; a famous German cory-breeder, who's book on breeding cory's is in the book section of Planetcatfish.
It says to 'brush' the bottom of the tank with a small, softhaired paintbrush.

I embroidered on his idea by attatching a small paintbrush parallel to a thin pvcpipe, wich is attached to a thin aquariumhose.
In effect I crossed a python with a brush to get a slow-suction vacuumcleaner, wich "brushes" the bottom of the tank.
The brush hairs just protrude before the opening of the thin pvc-tube, wich is glued to the tube, the whole length, by a few pieces of harmless cellotape.
When doing the daily waterchange (about 1/4 of the fry-tank) I wipe & suck the tank with this ïnvention"; actually it works rather well; although you have to be REALLY careful not to suck up fry.
But the WHOLE bottom needs to be vacuumed, because of the slow movement (fast moving will cost you fry) it's time consuming; the only drawback.
Bristlenosefry survive travelling through the hose, but cory-fry (in my case Hoplo-fry) do not.

To make a "back-up" I added a small herd of Ramshornsnails; these eat dirt, fungus, fungused eggs, foodrests, but no live fry.

Something that may be worth watching out for is an evil little bug that I have seen affecting Cichlid fry raised in bare aquaria, particularly following use of Methylene Blue when hatching eggs. It appears that under fairly sterile conditions (such as following use of Methylene Blue) this beast, Tetrahymena, goes from being a part of the normal scavenging aquarium microfauna to an opportunistic parasite. It is resistant to Meth. Blue, and when it finds itself in an environment where the only food source is fish fry it will attack them. I have seen Cichlid fry being digested alive by this, and it requires a treatment course of an anti-protozoal (Malachite Green and Formalin preparations work). Tetrahymena is fairly well known as a problem with Guppies raised in bare aquaria, but I have rarely heard mention of it with Cichlids, and yet it certainly can cause serious losses. With this in mind I have to wonder if this problem may also be a factor in losses seen in Catfish fry.
Pete[/i]

Thanks for all the info...what a mess this stuff seems to have become. We have been trying the Meth Blue on some. The Sterbai are spawning ever other, to every 3rd day, so hopefully we can figure this stuff out. We will probably try it ALL and see what helps! Something has to, we just have to find the right formula!

It gets to where the fry are getting all connected together by this stuff, forming a *clump*. We wipe the bottom of each container 2x a day (at least) morning and evening. Hoping the Meth will retard the growth of this stuff! I do have some of the Malachite Green and Formalin on hand , so will give that a try too.

All the ideas seem very logical, thanks for all the brain power!

Have a Wonderful Day
Monette

Just a thought.
What are the containers made of?

Food grade containers... ziplock brand.

I wonder if coating them with Polyurethane varnish would help, make them totally smooth instead of having a rough surface.

Pete

Would you think that these Tetrahymena could turn parasitic in normal conditions. I ask because there are occasions in some fry tanks, which have not been treated with methylene blue, that there have been a steady demise of fry. This is a problem that seems to be fairly common amongst cory breeders.
Ian

Coryman wrote: Would you think that these Tetrahymena could turn parasitic in normal conditions.

It's possible, but I haven't actually seen it happen. Over time they could damage the gills of young fish enough to leave them open to secondary infections which could lead to a slow diminishing in numbers. Hard to say though, I've only ever seen it as a problem in pretty sterile systems. It appears that following the use of Meth. Blue there is little competition from other micro-organisms, and not much else to act as a food source either. It appears that other Tetrahymena spp. may be obligate parasites, still others purely scavengers. Just out of interest, a Tetrahymena sp. is being considered as the next candidate to have it's genome studied!

Coryman wrote:I don't really have any problems with Methylene Blue but I never use it at the full recomended strength, usually at about half strength 1 drop per 2 Gal (9 ltr aprox)
There is another natural control for fungus and that is a little fresh water shrimp called Acileus (Not sure about the spellling) these are often caught with Daphnia, one placed on a container with eggs will help protect them as they feed on the fungus spores.

One thing to be very wary of is that Methylene Blue will greatly inhibit nitrification even at very low levels. This chemical should only be used with caution, as filter media stained with it will be unable to support bacterial colonies. No nitrification cycle will establish until the Meth. Blue has been removed by activated carbon or similar, and until this time the aquarium will be prone to ammonia problems without very regular (i.e. daily) water changes.

The name of the crustacean I believe you are after is Asellus, the Water Louse.[/quote]

Pete,




This is the critter I am talking about I wouldn't have thought of it as a louse though.

Ian

Water Louse
Scientific Name: Asellus species.
Group: Crustacea
Size:20mm

These animals are closely related to wood lice. Fourteen legs show that they are different from spiders and insects. They belong to the Crustacean family. The water louse is about 8mm long.

Hey you want to se them clean eggs, they just graze all over them keeping all the fungus at bay. It only wants one per batch of eggs though. If you have to many they breed and then there are problems when fry start hatching.

Ian

One thing to be very wary of is that Methylene Blue will greatly inhibit nitrification even at very low levels

Yes we do change water 2x per day (at a min)

And WOW what an ugly looking bug... but if it works! So let me get this straight..you place one of these bugs in with batch of eggs and they don't eat the eggs but keep them clean instead? Where would you aquire one of these?

Okay now the big

Do I have to TOUCH IT?

Bugs are NOT my forte' ... not even on the list of possibilities! But if it will save the Sterbai fry, I could use tweezers or something

Never ceases to amaze me, how much one can learn on the internet.
Thanks Guys!!

Monette

Acileus are not the sort of creature you can go to the pet store and buy. The yare not easy to come buy unless you collect your own Daphnia and then it needs to be from the right environment. Where I get mine from is a flooded woodland area near where I live. There is also an abundance of midge lavae at certain times, the trouble with these though is that the adults bite.

Ian

I currently use Ramshorn-snails (Planorbis sp) with great succes in with my baby Hoplo's.
Actually this was a great tip from a guy breeding Synodontis petricola and S "polli-green".
The Ramshorns eat dead fry, fungused eggs and all the "sticky dirt" on the glass-floor.
It seems you can use the Malaysian burrowing snail for this too, although I'm not a fan of this one. I always was under the assumption, these were carnivorous, and I certainly wouldn't thrust them with tiny syno-eggs.
I've got the new "Welse-atlas" from the famous German Mergus-books; and in this book are clear photographs that show this snailspecies eating empty eggshells and leaving live eggs and fry unharmed!! In this case Loricariid-eggs; p 269.

I also use Acriflavine to avoid fungus and funguslike growths on glass or eggs; this chemical is also used by those German catfishbreeders (p 267, Welse-atlas) it is much less harmful than methylene blue etc.

Hi!

Are you sure that they do not touch the good eggs, I have heard and experience some snail as well to keep a nursery "clean", but the snail did not make any difference between good, bad eggs...
Cheers
Yann

Thanks for the info Ian.... but when you said *adults bite* , you lost me LOL

Although it has been very frustrating
We will find some way of beating this fungus stuff!

trying different substrates also...

Thanks
Monette

Hi Yann, it depends on snail species...
I'm still not completely convinced about the Malaysian burrowers, but it's documented...check out the "Welse-atlas"! it's the newest book around (on loricariids of course, but hey, maybe Loricaria-eggs and Cory-eggs are a bit the same; the size doesn't differ too much!
the Ramshorn(planorbis) is harmless to fry at least.. The Pondsnai (physia)l however is not; these are oppertunists that eat anything.
I've never used Applesnails (too risky, if one dies, the whole fry-tank would be poisoned; big snail!) for this.
Just checked the Hoplo's -one week old now- still doing OK.

Monette

Its ay certain times of the year that the adult midges that bite when I collect the Daphnia.

Ian

Update...in the container we were/are having the fungus problem. After trying many things we tried a small substrate in the container. It seems to be helping. Mortality rate is improving.

My theroy is that the fry moving along the substrate helps rub the fungus off their bodies.

Nothing conclusive, but was wondering if anyone else has experienced this?

Thanks
Monette

I seem to be having similar problems, except the fry are dying after the first day or two.
Fry were almost all corydoras aeneus with possibly a couple of trilineatus.

-I'm moving the eggs from the community tank, then hatching them in a 'clean' tank and moving the fry to a raising tank.
-The tank seems clean, water change every day (water is kept in large bucket and aerated so it is consistent for changes), light aeration, removal of anything fuzzy (dead fry or bits of floatsome) twice to three times daily.
-I haven't started feeding yet (still yolk sack left on all fry).
-I'm using anti bacterial/fungal MarOxy from the egg stage on.
-Fry seem lively, cluster together on bottom of tank.
-After first day a couple of fry appear to be bent backward. No fungus is visible. The fry are either dead or near death.
-I have tried removing the dead and dying fry and medicating.
-I have tried removing all good fry to a clean tank and medicating.
-I have tried a shallow layer of sand in the tank.
-I have tried a bare bottom tank.
-I have tried small snails (ramshorns, trumpets, baby mystery) they seem to make things worse in the bare tank, the baby mystery snails actually die and create fungus outbreaks.
(By the way, Apple snails will eat eggs and fry if they are bigger than hatchlings.)
-By the second day nearly half of the fry are gone, fuzz can be seen on some of the dead fry, and most have the bent back.
-By the third day all of the fry are dead.

This has happened three times within the past few months. The first batch of fry was from my Pepper corys, the other two were mostly corydoras aeneus.

The really frustrating part is that I have successfully raised hundreds of corydoras aeneus a couple of years ago. Of course I didn't really have the space for them then, so they had overwhelming survival rates.

Suggestions? Opinions?

Thanks
Pam Spencer

Pam

The bent backs tend to point to one of two things.

The first being your breeding stock, deformaties start occuring when a particular line is constantly bred generation after generation without any new blood being added to the line.

The second, which is the more likely reason is water. You don't give the water perameters! I have had exactly the same problem over the the last year or so, and I narrowed it down the Nitrates. The first time I became aware of the problem I was with some very rare and expensive Cory's, the first two batches were fine but with the third fry were droping like flies and were deformed, in fact those that did survive were lacking their dorsal fins when the water was checked the nitrate lreading was 50 ppm. Later broods have been fine but I am always checking the water for nitrate, even the mains water has levels up to 40 ppm.

The next time they breed I would check for nitrates!

Ian

Thanks Ian

I never thought to retest the water, as I was doing large changes every day. I will keep an eye out for that.

I'll also watch for ammonia levels, as our tap water tends to get some nasty ammonia peaks once in a while.

The bronze corys could be suffering slightly from inbreeding before I got them. I don't know for certain that they are not related, just that I got them from two different local sources. I think I'll get some new stock. Hopefully there will be some nice ones at the big CAS auction next month, otherwise I'll try and get some through our breeders association.

I am almost 100% certain the trilineatus are not related, but they spawned at the same time, in the same tanks with the bronze so I don't know if any hatched or not. I have eight; three are my original females, three males were purchased a year later, and the last two females (sold as julii) were purchased six months later than the males. The three groups were bought through three different stores that all have different suppliers, so the chances of inbreeding are slim for them.

One small bonus... I discovered one peppered cory (paleatus) baby in the corner filter of the parentsâ?? tank last night.

Thanks again
Pam

Pam; what happened to you is almost exactly what happened to me with Hoplo fry and eggs.
But it got less once I let the fry tank get "dirty" (??)
Rigght now; there's algae growing on everything, even the filtersponge; only green and brown, no blue-greens mind.
And since then, I only lost a few baby Hoplo's. The rest seem to grow faster and they're eating again (before; the tank was scupulously cleaned by me, and the only thing the fry did, was lying on the bottom dying; refusing to eat anything, even the snails died, probably the acriflavine -wich I used to kill the fungus- finished them)
I feed live baby brine; microworms and powderfood.
One of my tricks: I still exchange water; once or twice a week (no more than 1/3!! or they start dying again); when I add the fresh water; I use an airhose as syphon from bucket to tank, so the new water goes VERY SLOWLY in the tank. I learned that fry is very sensitive to changing waterparameters. They can cope better with dirt than with changes in the waterchemistry....

Some years ago; it was MUCH easier to breed fish like this; I raised 120 Hoplo's from eggs (among those my current parents from the fry) with changing 1/3 of the water every two days and fed them nothing but crushed live tubifex, since they refused anything else! talk about polluting food....
IMO it's the tapwater that is changed since then: polluted, poisoned, nitrated; you name it; it's all over the hobby: the waterquality has declined rapidly and we're still drinking this stuff....
Currenly there are whole cities in wich it is now impossible to breed certain fish (in the Netherlands) and the watercompanies put all kinds of additives in it too; without mentioning it of course..