PROBLEMS WITH DYING FRY

[cartouche]

Hello, I would need some advice. In fact, I would need it quite urgently.

I was breeding Corydoras duplicareus for about 2,5 years and although they needed special water for the development of eggs, it went relatively well. However, in December 2005 I started to observe that the fry die 4-5 days after hatching. At first I thought that it was due to some chemicals in tap water, so I tried other water mixtures, rain water+well water, distilled water+well water, and even packeged water from the shop. But nothing worked effectively; sometimes a part of the fry survived, but the result was not significantly better.

After one year, when I was able to raise only several tens of duplicareus fry and I began to resign to it, I started to breed Corydoras trilineatus. The beginnings were not easy, from some unknown reason almost all the eggs turned white the second or third day, but after 2-3 months it improved somehow. Yet again, the fry behave in a similar way like duplicareus fry and die 4-5 days after hatching. This is really too much for my nervous system! Especially when I consider that like duplicareus, they die irrespectively of what a sort of water I use. At the same time, the fry of Corydoras sterbai and napoensis develop normally! Damn, what happens with the fish???

I know that it is hard to judge it, when I describe it only in words, hence I made a short video, where you can see, how the fry behave: The first days after hatching, they seem fine, but on 3rd-4th day I can observe first loses. The fry begin to suddenly shake or curl, lie apaticly on the side, sometimes even spring to the water surface and subsequently passively fall to the bottom. They also refuse to eat offered artemia with which I start to feed on 4th or 5th day. In the duplicareus I can see that they are not able to consume their yolk sac. Even after 5 days, they have yolk sacs virtually of the same size like after hatching. The 5th day after hatching, the mortality is often 100%.

http://www.youtube.com/watch?v=D1LO0ich3Ok

In the video, you can see a piece of trilineatus fry that just started to shake. There are also other pieces of fry, some lying on the side and half-dead already. I am virtually down at heel. Don't you have some suggestions?

I think the problem isn't in the water. So in what is it? I tried to change and enrich the diet of adult fish, but nothing changed. Recently I even fantasize that the dying may be due to bacteria or fungus in the air of the fishhouse that get into water through the air-stone. From time to time I observe that sensitive eggs of some species (like duplicareus) massly desintegrate and fungus without any reason. I was told that this is due to the heavy concentration of anaerobic bacteria in the unaired room. A frequent airing or a drop of methylene blue usually helps against it. But it doesnt help in the case of the dying fry.

[Coryman]

cartouche,

The one important thing that have not told us is your feeding regime. Personally I don't think it has anything to do with the water parameters. I would say that the fry have starved to death.

Ian

[cartouche]

cartouche,

The one important thing that have not told us is your feeding regime. Personally I don't think it has anything to do with the water parameters. I would say that the fry have starved to death.

Ian

Well, I also thought about it - in the case of trilineatus. Some of the fry really look like if they starved. I just will try to start feeding on the 3rd day already. However, I rather think that they simply don't eat from some reason.

Moreover, I really don't think that starvation is the reason of death in all the fry - and especially in the fry of duplicareus. I know how the fry of duplicareus developed, when it went well. They consumed their yolk sac after 4 days and I fed them on the 4th day. But now, in those few who survive, it lasts 5-6 days. I don't understand it... Then I start feeding (and they really eat). I tried to feed them on the 4th day like before, but they didn't eat. As I said, they behave strangely, shake, quickly breathe and then lie apaticly on the side. Sometimes they try to get to the surface like if there was no oxygen in the water. Somebody suggested me that they die because of infusoria in the water. So I removed them into a clean water shortly after hatching, but it had zero effect. Really, it's a mystery...

As for my feeding regime, I feed my fry with live artemia. Only in the case of napoensis, who are tiny, I use a powder from the fish flour for the first 1-2 days. I also used decapsulated artemia, but they are not so easy to buy. In sterbai and napoensis, I start feeding 3,5-4 days after hatching and I tried the same in trilineatus. I fed them with Chinese artemia, but I actually don't know, if they are not too large for them. Maybe they can't eat them because of their size, I don't know. I have never had any experience with trilineatus before.

[Coryman]

I am a little concerned about the fact that you say it takes the fry 4-5 days to consume their yoke sack, in all the Corys I have ever bred I have never had any that take that long, at the very most 3 days. I always offer food on the third day after hatching and the first food I always give is microworm, unless I am dealing with any of the elegans types, then I will use a paste made from flake mixed with the green Sera fry food.

I am certain that your problem is more one of feeding than water. I had a friend who years ago was probably the first to breed C. adolfoi and he found that they would not or could not eat, so he would spawn his C. paleatus and put the two lots of fry together when they hatched, he said it was like the C. paleatus fry would eat straight away and the adolfoi would mimic their actions, the result being that he raised about 80% of his C. adolfoi where as before he was loosing almost all of them and he kept them warm at 82º - 84ºF.

My duplicareus are now spawning regularly and I also keep them on the warm side at 80ºF. I actually raise them with the adults in a tank loaded with Java moss.

Ian

[cartouche]

At this moment I have only few trilineatus fry. Today I tried to feed a group of six pieces (3 days old) with live artemia; two are dead already, two don't eat, are lethargic and will almost certainly die, two have orange bellies - which means that they ate it.

I have another group of ca. 10-15 pieces that will be 3 days old today (Thursday). I will try it again, but it's clear that I can't feed them after mere 2 days, because their yolk sacs are still large. Grouping them with another species is problematic, because I mostly breed species that won't spawn, when I wish it. But I already had some trilineatus in a tank with other species and the result was that the trilineatus fry all died. In fact, out of more than 1000 eggs that they have given to me since December, I have less than 10 pieces of fry.

Currently I also have almost no eggs from duplicareus, because they have a breeding pause. But I can say that they really don't consume their yolk sac from some reason. They have very big bellies even after 4-5 days. When they develop normally, they gradually consume it and are quite lean after several days. However, when their big bellies don't disappear, I can predict with 100% certainty that they will be dead after those 4-5 days. If I have some new eggs and fry of duplicareus in the next days, I will make another video. You will then see that normally developing 4-days old fry don't look like these duplicareus.

[Coryman]

Do you only use BBS as the first food? I have found this not suitable for all species. Do you not use micro worm.

Also what triggering method do you use to induce spawnings.

Ian

[cartouche]

Do you only use BBS as the first food? I have found this not suitable for all species. Do you not use micro worm.

Also what triggering method do you use to induce spawnings.

Ian

I have no experience with microworms. I would rather prefer Paramecium, but I can't get to any clean culture. But as I said, it has hardly anything to do with feeding. By the way, most of the trilineatus that I spoke about above were dead before 3rd day. But during the last days I observed something: My little sterbai (luckily hatched from chronically fungusing eggs) behaved the same way, i.e. didn't eat, didn't consume their yolk sac and eventually died, if I started to feed them one day earlier than usually. Perhaps the water really contains some bacteria or infusoria that prevent the fry from normal development.

I just have new eggs from duplicareus and if they hatch, I will try to make some videos or photos, how the fry develop.

[apistomaster]

What you describe is very much like the experience I have had with Corydoras sterbai.
I am a member of Ian's forum also.
I have raised almost 1000 C. sterbai this season from about 8000 eggs. Some batches have very good survival rates and some bomb completely. Most are ending up with only about 20% survival. I have a large breeding colony and set up multiple tanks at a time

I usually feed microworm, decapsulated brine shrimp cysts and later, bbs. That first week of free swimmong is the deadliest for me when things go wrong.

I have had good results in both clean and dirty tanks. Thin fine sand substrate and bare bottoms. And every thing in between. Doesn't matter if I use my tapwater or make up softer water by mixing tap with RO water When it goes right, great but when it doesn't I might start out with 200 eggs and end up with only 40 fry. I just can't find a pattern in the results. I'm talking about an awfully large number of spawns and experiments.

Those that go wrong are doing exactly the same thing as yours. You have had good spawns and now you aren't
and neither am I. It sounds like we are both experienced although I have always had microworms because they are really well suited food for Corydoras fry.

It would be nice to resolve this. For me it is too inefficient. I am raising fish for fun, to be sure, but I also do it for money so getting good production is very important to me. I don't like having so many tanks tied up trying to reach a quota. I would rather have them freed up for other species.

[cartouche]

What you describe is very much like the experience I have had with Corydoras sterbai.
I am a member of Ian's forum also.
I have raised almost 1000 C. sterbai this season from about 8000 eggs. Some batches have very good survival rates and some bomb completely. Most are ending up with only about 20% survival. I have a large breeding colony and set up multiple tanks at a time

I usually feed microworm, decapsulated brine shrimp cysts and later, bbs. That first week of free swimmong is the deadliest for me when things go wrong.

I have had good results in both clean and dirty tanks. Thin fine sand substrate and bare bottoms. And every thing in between. Doesn't matter if I use my tapwater or make up softer water by mixing tap with RO water When it goes right, great but when it doesn't I might start out with 200 eggs and end up with only 40 fry. I just can't find a pattern in the results. I'm talking about an awfully large number of spawns and experiments.

Those that go wrong are doing exactly the same thing as yours. You have had good spawns and now you aren't
and neither am I. It sounds like we are both experienced although I have always had microworms because they are really well suited food for Corydoras fry.

It would be nice to resolve this. For me it is too inefficient. I am raising fish for fun, to be sure, but I also do it for money so getting good production is very important to me. I don't like having so many tanks tied up trying to reach a quota. I would rather have them freed up for other species.

So you say that your fry also die shortly after hatching? You can look at my video (link see above) with a little trilineatus fry, about 3 days old. The fry don't consume their yolk sac, start to shake and then lie lethargicly on the bottom.

The worst thing for me is that the only species that I can now normally breed is Napoensis. The fry of Sterbai and Barbatus develop normally, but I have collected only few pieces so far, because most of the eggs fungus before hatching; on the contrary, eggs of duplicareus and trilineatus mostly harch without problems, but the fry subsequently die.

As I said, it started one year ago. I have never had similar problems before. I suspect that there are some bacteria in the air or something that gets into water via the air stone, because it has nothing to do with the sort of water I use. It actually started after I began to expand my fishhouse. More tanks means more moisture and perhaps more bacteria and fungus spora in the air. Certainly, they are there, especially if I don't air the room - I wrote elsewhere that I had had a case with chronically fungusing eggs of duplicareus. I solved it only after I either started to add methylene blue into water or aired the room very frequently.

Or maybe I understimate the negative influence of the disintegrating egg remains. In any case, if the duplicareus now hatch (23 eggs), I will try to remove the larvae into a bigger container with clean water. I will also try to use an allegedly very effective desinfection called ESHA 2000.

[apistomaster]

I forgt to mention that I have used methylene blue as well. I get both good and bad results with or with out it so I don't think that is the problem.

Sometimes the losses are before hatching. I'll get a good hatch but have the high losses.
It isn't that the yolks are not absorbed on schedule. It begins after they should be searching for food but they barely move, get weaker and then die. Generally there are those 20% that are unaffected and eat from the beginning and develop normally. It doesn't seem likely it's the breeders. They have batches with 80% hatches and surviving fry. Taking the good and the bad it still works out to about only 20% survival.

I do suspect a bacterial infection is involved but nothing general to a houshold environment but rather a fish disease organism. I will actually checkout some of these under the microscope next time I have fry. I have been lazy about that. Bacteria are almost hopeless to treat these days on all fish let alone neonatals.

[corydoras]

I used to have this problem with sterbai fry, I killed thousands until I started adding the equivalent of half a teaspoon of salt per gallon to the hatching water. Problem solved. I tend to think that it could have been velvet.

Cheers

Matt

[Coryman]

Do you only use BBS as the first food? I have found this not suitable for all species. Do you not use micro worm.

Also what triggering method do you use to induce spawnings.

Ian

I have no experience with microworms. I would rather prefer Paramecium, but I can't get to any clean culture. But as I said, it has hardly anything to do with feeding. By the way, most of the trilineatus that I spoke about above were dead before 3rd day. But during the last days I observed something: My little sterbai (luckily hatched from chronically fungusing eggs) behaved the same way, i.e. didn't eat, didn't consume their yolk sac and eventually died, if I started to feed them one day earlier than usually. Perhaps the water really contains some bacteria or infusoria that prevent the fry from normal development.

I just have new eggs from duplicareus and if they hatch, I will try to make some videos or photos, how the fry develop.

I did ask another question "What triggering method do you use to induce spawnings" If I remember right you favour the use of hormones, is this how you trigger these so called problem species?

Ian

[Coryologist]

I used to have this problem with sterbai fry, I killed thousands until I started adding the equivalent of half a teaspoon of salt per gallon to the hatching water. Problem solved. I tend to think that it could have been velvet.

Cheers

Matt

Hi Matt. As someone who has used salt as a prophylactic for years in raising guppies, I find it hard to see how such a small amount of salt could make a difference. If you measure the salinity of a gallon of water, with and without the half teaspoon of salt, I believe you will find the difference in the readings to be imperceptible, if measurable at all without high-end lab equipment. Would be curious if you have ever taken the same batch of fry, split them into 2 groups and dosed one group?

Not challenging your assertion or trying to be argumentative. Just very curious, as many of us are looking for a way to reduce fry deaths, myself included. Thanks. - Frank

[apistomaster]

I totally agree. That is not enough salt to affect anything, negatively or positively.

I have actually been experimenting using a variety of approaches but the problem while generally chronic it is also very random. Can't get consitently good results by repeating the same method.

I don't subscribe to the old wives' tale that salt=death to Corys but when working with species native to relatively soft slightly acid waters adding salt isn't the first thought that comes to mind.

On the other hand, I am not averse to trying a set up with a teaspoon of salt per gallon. Might work.

That would close to the minimum amount of salt to have any medicinal effect.

[Coryologist]

I don't subscribe to the old wives' tale that salt=death to Corys but when working with species native to relatively soft slightly acid waters adding salt isn't the first thought that comes to mind.

On the other hand, I am not averse to trying a set up with a teaspoon of salt per gallon. Might work.

That would close to the minimum amount of salt to have any medicinal effect.

When I first started keeping Corys, they were all housed with my breeder guppies. I used a 1 tablespoon of kosher salt per gallon preventative treatment for the guppies and my Corys flourished and spawned with no problems. I no longer use salt since my guppie have been reduced by 90%.

If I were going to try any controlled experiments at this point, I would concentrate on alder cone solutions. I have had great success with this, but I must admit that I have no actual way to measure the concentration. I can tell you that in my experience it can double and even triple the hatching time and I am often forced to aid the fry in extricating themselves from their egg sac by using a fine camel hair brush. You can't knock a solution that can keep C. weitzmani eggs viable and fungus free for 20 days and get an almost 100% hatch rate.

My second choice would be formaldehyde, which in my fish room is my go to treatment of choice for most things. I had a group of irreplaceable Corys that I thought had a fungal infection. No fungus treatment helped, at all. Mr. Fuller opined that my problem might have been flagellates. He was totally correct, I dosed with formaldehyde at 3%, reduced to 1 teaspoon per 10 gallons and within 24 hours, only the most severely affected specimens showed any signs of having ever been infected. The fish that originally were the least infected, appeared as if they had never been infected at all. Additionally, the infestation was permanently eradicated.

Having wiped out half my fish room by an improper dilution to the correct ratio, I advise great care in using this treatment and please, triple check your math. I lost hundreds of Corys in the single worst fish room mishap in a 50+ year career. It still pains me to think about it.

I currently have 2 tanks ready for a controlled experiment. The next sizable spawning that takes place will be split between the 2 tanks. Haven't decided which I am going to try first, but I'm leaning toward the alder cones. I would always choose a natural treatment over a chemical one as a starting point.

I will keep you apprised of any results that I feel are viable. Regards. - Frank

[corydoras]

Hi Coryologist and Apistomaster

I agree that you would think that a half teaspoon of salt would be insignificant, but when it comes to velvet in particular (not sure about others), it has a definate effect. You only have to look to the killifish boys and girls where adding half to one teaspoon of salt per gallon is THE accepted way of stopping Nothobranchius killis getting velvet when kept in soft, acid water. It's not just Nothos either, many other killis are kept this way.

I did do a side by side experiment with and without salt and the results were so marked I've never gone back. I haven't done any further experimentation, the concentration I tried in the first instance worked so I haven't looked at it further.

I don't raise the fry in a constant salt solution though, I do start to dilute with fresh water changes when I switch the fry to BBS from microworm. However some salt level is probably maintained from the BBS.......

Cheers

Matt

[apistomaster]

I have been a member of the AKA beginning in 1968.
I have raised about 200 killiefish species and about 10 species of Nothos. Cleanliness is more important than salt. They do not occur naturally in salty water. Many Notho breeders do use salt but just as many do do not. I have tried both methods and it makes no difference to me. I still get good results either way. The most benefits from using a little salt is that the bbs live a few hours longer.
I am raising fewer killies now than I used to because they are not money maker but each summer I raise either some Austrolebias nigripinnis or A. alexandrii outdoors in wading pools in the summer because they are not really full fledged tropicals. I take them outdoors when they are about 1/2 inch long. I like the way they sparkle in the morning sun. They are spawning within another month or so and I provide them with weighted perware filled with peat and cut a 3 inch hole for them to access the peat. Simpsonichthys species are another group I like to work with and they are tropicals. I am also raising some Aphyosemion labarrei.

If your water is getting salty from using bbs then you must not be rinsing them well. I avoid unwanted salt build up, myself. Between rinsing the nauplii well and frequent water changes salt does not build up. I also use artificial sea salt mix for hatching brineshrimp because you can't beat the results. If I did not rinse my brineshrimp well it would not take long before I would drastically raise the TDS in my water beyond what I want for softwater fish.

I raise a lot of different fish; catfish, SA dwarf Cichlids, discus, killies, Tetras and other softwater fishes. My newest project is Coral Red Pencilfish. 18 are still in quarantine so it will be awhile before they will be ready to set up for spawning.
I have raised other Pencils but these are just so colorful they are worth all the tedious work involved with coaxing them to a size where their fry can take bbs. Until then pencils seem to grow in slow motion coompared to many other fish.

[hellocatfish]

Oh gosh, I hate to butt in here since I don't know diddly squat. But I was wondering...could it be that salt in some way mimics the properties of some substance that IS found in the cories' native waters? So even though yes, cories aren't normally salty critters, they're deriving a benefit that perhaps was provided by some other dissolved mineral.

And even if they don't derive a direct benefit, perhaps a predator or pathogen of the microorganisms that have been killing the fry is activated by the presence of salt and its correlating substance in the native waters.

Is there any kind of database you breeder folk consult that provides an up-to-date and extremely detailed analysis of native water chemistry? If so, can you all do a line-item comparison check for any mineral or substance that has properties or can be a catalyst in reactions similar to salt?

I know it's kind of far out and I have no experience whatsoever...in a way. But, back in the day though...I used to do very low-level security work for my company and caught an embezzler--even though I stink at accounting...go figure. I'm trained or have it ingrained in me to look for correlations that might seem odd or irrelevant to some, even if I don't have full grasp of all the particulars. Not having any experience with this field, however, I don't know what is already known and what has flat out been disproven.

I'm legitimately interested in the issue of salt because on a lark after reading some of its beneficial properties on stressed gills, I did use it this time in starting over my cory tanks and I've been amazed at how vibrant the fish have been so far...crossing fingers for luck. Of course, I've changed too many other variables to attribute the difference to salt with any great confidence.

Oh well, just throwing the question out there. Now retreating to my newbie lurking mode.

[MatsP]

Hellocatfish.

What you're referring to is "electrolytes", which is essential minerals in the body of all creatures.

However, aside from the need to have a small amount of all of the essential minerals present in either the food or the water, there is one thing they all do: that is affect the conductivity (most often measured as TDS - although TDS stands for "total dissolved solids", any TDS-meter is actually just a conductivity meter with a "divide by two" on the scale).

Most cories live in water with very low conductivity. From this, we can draw the conclusion that the amount of minerals in the water is very low. Whether these minerals are "aquarium salt" or other minerals of a more natural origin (such as Calcium carbonate that is "hardness" in the water I get out of the tap), it's not really important. The key is that the mineral content in nature, in most of the South American region, is very low.

I'm not aware of any database (it would be a nice thing to add to the "body of water" database that we have here, actually), but I've seen figures of conductivity and other water parameters when searching the web and looking in books like the Mergus Catfish Atlas.

--
Mats

[hellocatfish]

Thank Mats, for the info. Can you help me with another question? What is a trace element and is it relevant to filling in the gap of what may be causing problems with some of the breeders' work? For example I know people take trace elements in their vitamin supplements, and it's not much, but supposedly essential even at very low doses...er, have I got that right?

Is there anything glaringly missing from the tap water most of us use vs. Amazon water in terms of trace elements?

Has anyone tried that Tetra brand black water extract in their breeding programs and had luck with it? Today at the LFS when I was asking one of the guys about my panda cories and the fact they were keeping them there at the LFS at 7.0 and I had 7.8 tap, he suggested I go back to using the pH Buffer they had me using before. I said I wasn't sure about that and asked if the Tetra Blackwater extract would do the same thing and he said it might, and if I wanted to breed the cories (which I do NOT, heaven forbid!) then definitely the blackwater extract might help. I opted to mull it over.

Sorry this is my last question on this topic and I want you all to go back to what you are discussing without newbie blather. I guess I feel kind of intense curiosity about the possibility our tank cories are missing out something that enables their wild cousins to breed so successfully (so far as we can tell) despite predators and food shortages and pollution, etc.

Heck, maybe it's something as weird and basic as sharing their water with mosquitoes. Blechh!

[MatsP]

Thank Mats, for the info. Can you help me with another question? What is a trace element and is it relevant to filling in the gap of what may be causing problems with some of the breeders' work? For example I know people take trace elements in their vitamin supplements, and it's not much, but supposedly essential even at very low doses...er, have I got that right?

Trace elements are those minerals that the body don't require a lot of, but they do need some. Selenium, Iodine, Copper and so on.

Is there anything glaringly missing from the tap water most of us use vs. Amazon water in terms of trace elements?

I wouldn't think so. Water soluble minerals are quite often added to the tap-water to "improve it", and if you live in a high pH area [which I seem to remember you saying a while back], it's most likely because the water is high in calcium salts (hard water), which in turn usually means that it's got a lot of other minerals too since the calcium comes from heaps of dead microorganisms that have formed on the seabed, and the microorganisms will have contained other minerals too that got "stuck" in there.

Has anyone tried that Tetra brand black water extract in their breeding programs and had luck with it? Today at the LFS when I was asking one of the guys about my panda cories and the fact they were keeping them there at the LFS at 7.0 and I had 7.8 tap, he suggested I go back to using the pH Buffer they had me using before. I said I wasn't sure about that and asked if the Tetra Blackwater extract would do the same thing and he said it might, and if I wanted to breed the cories (which I do NOT, heaven forbid!) then definitely the blackwater extract might help. I opted to mull it over.

From what I understand, black-water extract is essentially "peat-tea", i.e. the result of boiling peat with water and bottling it.

It wouldn't contain much other than some humic acid, and probably not enough to change the pH on hard water.

I also don't really believe in "pH corrections". We have fairly hard water here in southern England. Almost all fish are fine in it. pH corection by adding something to the water would just increase the mineral content in the water, which is exactly what you DON'T want.
[/quote]

Sorry this is my last question on this topic and I want you all to go back to what you are discussing without newbie blather. I guess I feel kind of intense curiosity about the possibility our tank cories are missing out something that enables their wild cousins to breed so successfully (so far as we can tell) despite predators and food shortages and pollution, etc.

Soft water contains less minerals, so if anything, your water contains TOO MUCH... Almost all bodies of water in South America is soft-water - there are some exceptions, but if we should group them all in one category, then soft it is.

Unfortunately, you can't add something to the water to make hard water soft - at least not "trivial things". What you can do is get an RO or DI filter to REMOVE the minerals - it's rather expensive, but it does remove almost ANYTHING found in the water.

Heck, maybe it's something as weird and basic as sharing their water with mosquitoes. Blechh![/quote]

I don't think so. I'm pretty sure Ian Fuller (Coryman) hasn't got exotic mosquitos in his fish-room.

--
Mats

[apistomaster]

Hi Corydoras,
With regard to using salt with Nothobranchius itis true many other Notho breeders do indeed us salt.
I beliee you have a point with regard to breeding Nothos in soft acis water that salt is useful.
However, if your water has a pH of 7.0 to 7.8 and 100ppm/l. total hardness, salt is not necessary nor does it do any harm.
Salt has no magical properties. As I said before, I have been involved with breeding killies since 1968. Nothos are among the few that naturally occur in slightly alkaline and moderately hard water.
Most are soft acid water fish.
Cleanliness trumps salt as a velvet preventative any day. Some practices become traditional without any scientific basis simply because they seem to work empirically.
So much depends on the water an aquarists has coming from the tap. Most tapwater these days is kept above pH 7.0 and slightly alkaline by the municipal water suppliers to avoid corrosion of the pipes. That is just fine for fish like Nothos.

In the early days of killie keeping many breeders had softer acid water and they found that salt help. It helps most likely because it raises the TDS to which Nothos are better adapted to so therefore their immune systems are able to be more effective.

It is a case of getting the right results for the wrong reasons.
Oodinium also plagues marine fish and an effective treatment method often includes a freshwater dip. Oodinium is not sensitive to salt.

In any case the loses of Corys has yet to be shown to be the result of Oodinium infections. Next time I have a batch of Cory fry that are sick I will check for the presence of Oodinium infection under my microscope.

[cartouche]

Hi, the duplicareus just hatched. 20 out of 23 eggs so far, and the three remaining eggs also seem O.K., which is an excellent result considering that the range of ideal water chemistry is very narrow. I hatched the fry in a small 1,5 liter container and I already placed them into a bigger 3 liter container with new, but identical water, and I also added 1 drop of ESHA 2000. I am curious, what happens now.

[apistomaster]

You can't beat that percentage. I had a similar looking Corydoras spawn yesterday, C-121, about 40 eggs collected but about 6 or 8 are doubtful. They were very sticky and hard shelled. I wasn't exactly prepared for this so all I've done is to place them in a net breeder basket and hung it in the spawning tank. No treatment just going natural. It will be intersting to see whether most or any hatch but it looks like they are off to a fair beginning. This was the first time I found more than the odd egg here and there. I had either other fish or snails to screw up egg survival before.
I'll post the results in a few days.

[corydoras]

Hi Apistomaster

I was always of the belief that all marine diseases are different genera to freshwater diseases hence why freshwater dips are good for curing marine fish and vice versa for freshwater fish. No fish disease can cross over from fresh to marine and vice versa.

Marine velvet is an organism of the genera Amyloodinium whereas freshwater velvet is Piscinoodinium, so they actually different genera.

One cannot tolerate salt, one can. It's the same with white spot, the same common name for the disease in marine or fresh but two completely different organisms.

Next time you see a case of velvet on a freshwater fish, and I hope you don't, try a salt bath before anything else. It's like white spot, you literally see the protozoans fall off the fish as they implode via osmosis (the parasites, not the fish!)

Cheers

Matt

[apistomaster]

It is the presence of dissolved solids that is problematic for soft water fishes and more to the point, the ability of their eggs to hatch.

The commercial blackwater additives are good for making the water look right but peat filtration is a better way to actually simulate natural blackwater in my experience and it is much cheaper.

I am just naturally wary of all "miracles in a can" types of products. Besides, if you change water as much as I do, the commericial products are literally just money down the drain.

Re: velvet, I must get a more resistant form of velvet, particularly with wild bettas and killies. The chemical meds seem to work better for me than altering the salinity. It is mostly a problem if I've let water quality decline and/or overcrowding occur.
Both are lapses in good fish keeping practices which are my fault. The velvet is more of a consequence.

[corydoras]

I agree 100% with apistomaster and prevention is always better than a cure.Well maintains tanks rarely see disease and I must admit I only tend to see anything in fish that are in quarantine ie. recently undergone stress that has dropped their natural immunity.

Please don't think I'm a routine salt doser. In fact my sterbai are the only cory fry I need to dose to get them through the first 2 weeks, after that I have no problem with them. I have had no problems with panda, aeneus, elegans, pygmaeus, barbatus, adolfoi or paleatus.

Similarly with my Nothobranchius killies, I have hard alkaline wayer so I don't need to use salt. I have only seen velvet once in young fish (grabbing a wooden aquarium rack with both hands)and that was with a pair of kirkii a friend brought round. You could see the yellow sheen ontham in the bag. That's when I dipped and watched the parasites fall off before putting them into my tanks. In my experience, once elderly Notho's start to pick up velvet, they are at the end of their lifespan anyway.

Water and food - maintain high standards of both and you will have success so long as you add a little patience.

Cheers

Matt

[hellocatfish]

I'm so sorry to butt in again, but I feel very strongly that you all are missing a very important reason for adding salt to a cory tank. It makes them tastier! Mmmm....salted catfish...

Sorry, I couldn't resist...

[Jackster]

I know nothing about Corydoras but I have found salt useful to kill Chilodonella.
Earlier someone stated that 1/2 teaspoon of salt per gallon would be almost nothing,
however, I would disagree. I used approx a .1% salt concentration to kill the parasites
I had in my tank. This was 1 tablespoon (3 teaspoons) per 5 gallons and this concentration
was maintained for 14 days including adding the salt to water changes. I used pure
coarse kosher salt (mined) with absolutely no additives. I was never a believer in using
salt but for this purpose I found it magical. Other chemicals I tried didn't touch this tough
parasite. I also would recommend to not go higher than a .2% salt concentration unless
one were to use salt as a dip.

[apistomaster]

I have a lot of experience with Chilodonella and it takes a microscope to ascertain for certain which protozoan is afflicting you fish. Again, I found that malachite green based meds were quicker and more through of way of emliminating them. I don't use saltas the primary med.

My most recent outbreak was caused by a large selecton of small plecos I shipped in from the opposite side of the country and the disease was already very advanced,
By the time it fomrs noticeable symptoms on armorored sucker mouth cats the gillis have sustained heavey damage. The salt can be used inconjuction as a soothing medication and to promote healing as the chemicals begin to break th cycle of reinifection. I actually did use about a tablesoon of salt for a few days until I began noticing improvements but gradually diluted the salt by water changes as fast as I noticed pogress was being made.