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Freshwater Flounder?


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#1 moeberry

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Posted 23 May 2007 - 05:13 PM

Hi
I saw a fresh water flounder in my local pet shop. I was told that it would do fine in my fresh water tank, but upon researching on the net, I found that most so-called freshwater flounders need some salt in the water as they grow. So my question is how can I tell if it is one of the true fresh water fish or if it will need salt later on?

Please excuse me for not knowing the proper names.

Moeberry

#2 Fella

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Posted 23 May 2007 - 05:38 PM

Hi
I saw a fresh water flounder in my local pet shop. I was told that it would do fine in my fresh water tank, but upon researching on the net, I found that most so-called freshwater flounders need some salt in the water as they grow. So my question is how can I tell if it is one of the true fresh water fish or if it will need salt later on?

Please excuse me for not knowing the proper names.

Moeberry



I kept a true freshwater flounder, a brachirus harmandi, for some time. The give away was that it did not have a paddle tail, and the underside was mottled. Have a look on fishbase (www.fishbase.org) and search for all fish with the common name flounder. It may take some time...

Brachirus pan is one of the most frequently traded, although, I think the scientific name was changed for that some time ago.

#3 nmonks

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Posted 23 May 2007 - 06:38 PM

As Fella mentions, the tail fin is a good clue. Where most of the American soles (family Achiridae) have a large, paddle-like tail, the Asian soles (family Soleidae) tend to have a small tail that blends almost imperceptibly with the fins around the edge of the body, often tapering to a point. I've got a listing of some of the most common species in my FAQ.

Almost without exception, the species sold in the US is the subtropical hogchoker sole Trinectes maculatus, a species that needs brackish water. In Europe things are a bit more mixed, though species of Brachirus do seem to predominate. These are extremely difficult to identify to species level, the exception being Brachirus harmandi which, as Fella says, has a mottled underside (all the other species have plain pink or white).

Unless you know better, keep a sole in brackish water at SG 1.005 with moderately to hard water and a pH around 7.5. This will do freshwater species no harm at all and will benefit brackish water species immensely. Such a tank could also house guppies, mollies, gobies, etc. so doesn't cause any problems in terms of building a community. Plants aren't an issue, because soles want plain sand (not gravel) so you may as well skip plants or use species attached to wood/rocks like Java fern, Java moss, and Anubias.

Cheers, Neale

#4 OrganizedChaos69

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Posted 26 May 2007 - 12:20 AM

I have had freshwater flounder before, THey do well in a simple freshwater aqaurium. However, most freshwater fish do like some salt. It adds electrolytes, and slightly alkanizes the water. Use only salt made specifically for aqauriums as table salt can be harmful and add only the amount that the box tells you for every gallon of freshwater.

#5 andywg

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Posted 26 May 2007 - 01:41 PM

However, most freshwater fish do like some salt. It adds electrolytes, and slightly alkanizes the water. Use only salt made specifically for aqauriums as table salt can be harmful and add only the amount that the box tells you for every gallon of freshwater.

This is just old school fishkeeping without any science to back it up. Some freshwater fish are highly intollerant of salt in the water even in the short term. In the long term you are placing an increased pressure on the fishes' osmoregulatory systems as they are having to process water with more salt in it than they are evolved to do so.

Which electrolytes exactly are added, and why are they necessary for freshwater fish?

Also, aquarium salt is just sodium chloride, exactly the same as any other sodium chloride. So long as your table salt has no other additives then you can use it (and it is cheaper).

Do a search on salt in the main forum and you will find a number of scientific based results on why aquarium salt is little more than snake oil.

#6 OrganizedChaos69

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Posted 26 May 2007 - 07:35 PM

Thats your own opinion, and I couldnt' disagree more. Fish like some degree of electrolytes. Some are intolerant, but even those like some amount because it encourages slime coat production and thus protects the fish from bacteria. Actually thats the main benefit of salt, It encourages the slime coat to build. It's not oldschool, it's extremely current. I'd always reccomend some salt.

Ground contains salts, rivers ruun over the ground. Any river in the world that you go to, will have some salts in it.

Edited by OrganizedChaos69, 26 May 2007 - 07:36 PM.


#7 andywg

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Posted 26 May 2007 - 11:34 PM

Fish like some degree of electrolytes.


You still haven't said exactly which ones they are and why the fish want them. Until you can I think this is a null argument.

Some are intolerant, but even those like some amount


No. See, the word "intolerant" means they cannot tolerate it. In other words, some fish die with an extremely low amount of salt in the water. Previousl,y Bignose has found studies showing some species of cory die in extremely low amounts. These fish cannot be considered to be "liking the salt in small amounts" if they are dying from it.

because it encourages slime coat production and thus protects the fish from bacteria. Actually thats the main benefit of salt, It encourages the slime coat to build.


The main way that most (if not, all) slime coat additives work is to irritate the skin of the fish into producing more slime coat. Where is there any evidence that salt helps the slime coat rather than irritating the fish into producing more?

It's not oldschool, it's extremely current. I'd always reccomend some salt.


The use of aquarium salt came about from two outdated beliefs in early fishkeeping:

1) As "old water" was considered good, to prevent problems from nitrates and nitrites in the water, salt was added. This dulled the effects of poisoning the fish with the aforementioned nitrogenous waste compounds;

2) As FW fish maintain an internal salt level higher than the water around them, it was considered less stress on them to have a higher level of salts in the water. Unfortunately these earlier fishkeepers forgot that FW fish have evolved through millions of years to osmoregulate in the waters effectively devoid of salts, and by adding more it can cause problems with the osmoregulatory functions of the fish.

Nowadays people realise that water changes are far better than old water, and people try and keep the fish in water as close as possible to that in which the fish occur naturally.

Ground contains salts, rivers ruun over the ground. Any river in the world that you go to, will have some salts in it.

Indeed. But your tap water already has more salts in it than most of the South American waters. Freshwater rivers in SA (and most of Asia) contain less than 1ppm sodium chloride; an amount so small that even scientists don't bother to recount it any more accurately than "<1ppm" in degree level ichthyology texts.

Now then, since you claim the salt is so good for the fish, can you find any scientific evidence to support your statements that all fish benefit from salt in the water, even those that it kills in small quantities?

Edited by andywg, 26 May 2007 - 11:37 PM.


#8 OrganizedChaos69

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Posted 27 May 2007 - 01:54 AM

"Indeed. But your tap water already has more
salts in it than most of the South American waters."


Not my tap water. And no they aren't intolerant in general, they are intolerant to CERTAIN levels. Electrolytes is a self explanatory word. It means ions from the periodic table of elements that fish use in nature to help build their slime coats. These include sodium +1, Magnesium +1, Chloride +1, Iodide +1 among others. Is that specicfic enough?

And no it has nothing to do with iritationof the skin to force more slime, the slime that the fish use are made from compounds containing these ions. When there are not enough of these ions in the water, the slime coat is limited, if there are too much, and the fish can remove them, they will begin froming harmful compounds as the fish cannot find the other neccessary ions to bond with these. Ions need to bond because they want a noble gas configuration. If there are not enough healthy ions to connect to these salt ions, then other harmful ions will begin to connect to these extra ions and this is what harms the fish if they cannot filter the new compounds.

Edited by OrganizedChaos69, 27 May 2007 - 01:56 AM.


#9 andywg

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Posted 27 May 2007 - 12:08 PM

Not my tap water.


So you can test the level of salt in your water to a higher degree than scientists even bother mentioning in a degree level text. I hope you can forgive me for doubting the above assertion.

And no they aren't intolerant in general, they are intolerant to CERTAIN levels.


Yes, and in some fish that level is extremely low.

Electrolytes is a self explanatory word. It means ions from the periodic table of elements that fish use in nature to help build their slime coats. These include sodium +1, Magnesium +1, Chloride +1, Iodide +1 among others. Is that specicfic enough?



How will magnesium be introduced into the water by the very nearly pure sodium chloride in aquarium salt? Or iodode? Aquarium salt is nothing more than table salt: sodium chloride, and often includes an anti caking agent to make it pour nicely. I do not

And no it has nothing to do with iritationof the skin to force more slime, the slime that the fish use are made from compounds containing these ions. When there are not enough of these ions in the water, the slime coat is limited, if there are too much, and the fish can remove them, they will begin froming harmful compounds as the fish cannot find the other neccessary ions to bond with these. Ions need to bond because they want a noble gas configuration. If there are not enough healthy ions to connect to these salt ions, then other harmful ions will begin to connect to these extra ions and this is what harms the fish if they cannot filter the new compounds.


Do you have any scientific texts to back that up? I find it hard to believe that fish such as South American Characins that live in salt and ion poor waters will suddenly feel so much better with salt in the water. I also find it hard to believe that fish that are evolved to live in waters free of these ions in the wild will suddenly have problems in an aquarium setting.

nmonks has previously commented on the slime coat:

Fish produce extra-thick slime coats when their skins are irritated. If you want a human analogy, it's getting a callous on our feet when we walk barefoot a lot or in poorly-fitting shoes. Our skin responds to the stress by developing a coat of dead skin cells that protect the living tissues within. Likewise, where fish are irritated, their produce extra mucous on the skin to protect themselves. A fish should have a perfectly adequate slime layer under its optimal conditions (which, for angelfish and discus, would be very soft water at about pH 6). Secondly, I do not dispute that salt is useful for treatment. But there's a difference between using salt as a short-term tonic in the aquarium and using salt all the time. I don't know any professional aquarists who recommend the latter. Rather, experienced aquarists put the accent on water quality and trying to match the water chemistry of the fish's natural habitat.


Interesting to note the point I have put in bold above.

From reading Biology of Fishes 2nd edition by Bond, I note that the slime coat (or mucus) consists largely of glycoproteins that can absorb large amounts of water. I am no expert on glycoproteins, but my short reading indicates that sodium or chloride ions are not component parts (their make up is of a protein and a carbohydrate). I also can't find any references to fish needing these electrolytes in the water (including the ones not present in aquarium salt) in order to create mucus.

In the two degree level ichyology biology texts I have (one being mentioned above, the other being Ichthyology: An Introduction to Fish Biology 5th Edition by Cech and Moyle) the only mention of electrolytes is in relation to the electricity producing cells in electric fishes. The only mention of ions is in relation to osmoregulation, and I have detailed above that increased salt levels will place unnecessary strain on freshwater fishes evolved for water without salts in them.

However, if you have more recent studies that the above two texts would not have considered when writing I would be interesting to see them.

#10 OrganizedChaos69

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Posted 27 May 2007 - 06:06 PM

How will magnesium be introduced into the water by the very nearly pure sodium chloride in aquarium salt? Or iodode? Aquarium salt is nothing more than table salt: sodium chloride, and often includes an anti caking agent to make it pour nicely. I do not


=====================

Because these aquarium salts are sea salts, and the majority of sea salts are actually magnesium salts, not sodium salts.

#11 andywg

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Posted 27 May 2007 - 06:23 PM

Because these aquarium salts are sea salts, and the majority of sea salts are actually magnesium salts, not sodium salts.

Aquarium salt for freshwater fish (as sold by your lfs for freshwater aquaria) is pretty much pure sodium chloride.

Sea salt is around 75-80% sodium chloride. The rest of the elements buffer the water increasing alkalinity and raising the pH towards 7.8-8.2.

Those last two factors make sea salt completely the wrong thing to add to any tank containing soft water fish that require low alkalinity and a pH closer to 6.

#12 OrganizedChaos69

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Posted 27 May 2007 - 08:24 PM

sodium chloride.

======

Sodium Chloride is table salt.

Actually you were right about there being more of this than magnesium salts in the ocean, but Magnesium is second to sodium compounds in the ocean.
http://en.wikipedia.org/wiki/Seawater

=====

And you can continue to argue until your hearts content, but I always strongly encourage using salt in freshwater aquariums as long as you follow the instructions on the salt container and as long as it is specifically made for aquariums. You can think as you like, but I use salt with great results and I will continue to give it as advice to everyone I meet.

Edited by OrganizedChaos69, 27 May 2007 - 08:25 PM.


#13 ac106

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Posted 27 May 2007 - 08:31 PM

=====

And you can continue to argue until your hearts content, but I always strongly encourage using salt in freshwater aquariums as long as you follow the instructions on the salt container and as long as it is specifically made for aquariums. You can think as you like, but I use salt with great results and I will continue to give it as advice to everyone I meet.



I applaud you for sticking to you guns in the face of overwhelming logic and scientific fact. Bravo.

#14 OrganizedChaos69

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Posted 27 May 2007 - 08:59 PM

What overwhelming logic?

#15 OohFeeshy

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Posted 27 May 2007 - 09:01 PM

Well, for instance the fact you've conventiently ignored the facts about slime coats...

#16 nmonks

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Posted 27 May 2007 - 09:10 PM

Well, people are having fun here!

The relative proportions of the elements sodium, chlorine, magnesium etc in seawater depends on how you measure them, by weight or by concentration. By concentration, which is what actually matters from a biological perspective, sodium and chlorine are by far the most abundant elements (after hydrogen and oxygen of course), with magnesium, sulphur, potassium, and calcium being way, way less abundant than those two. All the other stuff, carbon, strontium, iodine, etc are present in seawater in tiny amounts.

Now, if you measure things by weight, the order becomes different because elements have different weights themselves, so potentially a rare but heavy element can be a larger proportion of the weight of seawater than its concentration (i.e., sheer abundance) might suggest. So chlorine, which is numerically less common in seawater than sodium, actually accounts for almost twice the weight of seawater than sodium does. This is because although chlorine is less common than sodium in the seawater, chlorine has almost twice the atomic weight.

In other words, when talking about what's "most important" in seawater you need to decide if you're talking about the weight of the elements or the concentration of those elements.

As to be bigger question of is salt required in a freshwater aquarium. Absolutely not. This is unambiguous. Just like carbon, it's something from the past that aquarists buy because advertisers tell them. It's cheap and promises a lot, so people buy the stuff. Just like carbon. It costs next to nothing to make and can be sold at a whacking great mark-up, meaning there's lots of profit. Just like carbon.

If you're asking does it do any harm, that's a difficult question to answer. Freshwater fish can often tolerate a bit of salt without any problems at all. Many major fish groups -- livebearers, cichlids, and killis for example -- are descended from marine fish and have some of the "marine hardware" still inside their bodies. Guppies can be adapted to twice normal seawater salinity, for example, and a variety of tilapia and Central American cichlids will breed quite happily in normal seawater. Even things like catfish and barbs have considerable salt tolerance in the wild and live in brackish waters, and there are even a few brackish water tetras (e.g., x-ray tetra) and gouramis (e.g., giant gourami).

But once you start looking at fishes that have become specialised to very narrow sets of water parameters, things get different. The classic example is Malawi Bloat, a problem with (surprise) Rift Valley cichlids where the owners have used sea salt in an attempt to harden the water. The result is organ damage and eventually death.

Adding tiny amounts of salt (the "teaspoon per 5 gallon" sorts of things) probably don't make any difference either way for most regular community fish. It may slightly offset the harm caused by nitrate accumulation in the water, but that would be better fixed using water changes and fast-growing plants. Tiny amounts of salt don't have any effect on fungus or whitespot, and treating those things is much safer and more reliable in most cases with standard medications. Any small benefits accrued by using salt are, in my opinion, outweighed by the potential damage caused to those fish intolerant of salt. Certainly fishes adapted to blackwater conditions as well as Rift Valley cichlids will not do well with the addition of salt and can potentially be harmed by it.

Cheers, Neale

#17 OrganizedChaos69

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Posted 27 May 2007 - 09:47 PM

I haven't seen any facts from the person I was arguing with.

Here it is. Dr. Wellfish's aquarium salt.

Helps by improving the gill function and reducing stress.

During stress and disease, healthy gill function (osmoregulation) is disturbed. This can lead to the loss of electrolytes through the gills (sometimes called osmotic shock). This reduces the intake of oxygen and release of carbon dioxide from the fish. Aquarium salt reduces electrolyte loss and promotes healthy gill function.

There straight from the box, which is sold in pet stores across the US. It's not an old technique or myth. It's a fact. Used everywhere. I worked at petsmart last year and every day we had to had cups of this salt to the sump pumps for the freshwater fish. Trust me you to don't know what your talking about, it's a common method of reducing stress from fish and keeping them healthy. You have the right to your opinions, wrong or not.

#18 Maximus

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Posted 27 May 2007 - 10:02 PM

Your right, Petsmart are renound for their quality of fish...

#19 OrganizedChaos69

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Posted 27 May 2007 - 10:04 PM

Actually they are.. Of all chain stores, petsmart has the healthiest fish. I've worked at petsmart, and petco among other fish stores. Including the "Aquarium Center" Ranked 2nd on the east coast.

THe Aquarium center, not a chain store used salt as well, and had just as healthy fish as petsmart, petco however was rancid, and ironically, they didn't use salt. Again I don't know where your from, but if your from Maryland and the east coast, I'm right, deal with it.

Edited by OrganizedChaos69, 27 May 2007 - 10:04 PM.


#20 nmonks

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Posted 27 May 2007 - 10:12 PM

I haven't seen any facts from the person I was arguing with.

I'm not sure anyone advocating giving fish the same environment in the aquarium as they enjoy in the wild needs to prove their case. Keeping Rift Valley cichlids in hard, alkaline water or blackwater fish in soft, acid water is probably a pretty safe approach. That said, there are *some* fish that seem to need different conditions in the aquarium to those they enjoy in the wild. Bumblebee gobies for example inhabit (in some case) blackwater streams but seem to be easier to keep in brackish water. Mollies are primarily freshwater fish in the wild, but again, do well in brackish water. What still needs to be demonstrated is whether or not adding salt as a matter of course helps with definitely freshwater things like neons and angelfish. There's no evidence I'm aware of that it does.

Here it is. Dr. Wellfish's aquarium salt.

Dr. Wellfish -- bless his little cotton socks -- is in this game for the money. He sells activated carbon as well, something that is even less useful than salt. Look, candy bar companies and soda manufacturers will tell you their products are a useful part of a balanced diet. Few nutritionists would agree. People selling things have a vested interest in making those things sound useful to you.

Helps by improving the gill function and reducing stress.

Pretty vague things. Ever seen those adverts from the 1890s where people were selling magnetic hats and cocaine-laced baby food? Invariably they said things like "improves circulation" and "reduces stress". Snake-oil claims don't change, and provided people are ignorant of basic science (or even common sense for that matter) then people will sell this stuff.

During stress and disease, healthy gill function (osmoregulation) is disturbed. This can lead to the loss of electrolytes through the gills (sometimes called osmotic shock). This reduces the intake of oxygen and release of carbon dioxide from the fish. Aquarium salt reduces electrolyte loss and promotes healthy gill function.

As I've said elsewhere, as part of a therapy, salt may have value. It certainly can be used as a "drug". Sick people are put on saline drips, but that doesn't mean we should be drinking seawater every day. Besides, if you have a sick fish, then whether it lives or dies will have nothing to do with electrolytes. Clean water, proper diet, correct water chemistry -- these are the things that help, plus proper medication where appropriate.

There straight from the box, which is sold in pet stores across the US. It's not an old technique or myth. It's a fact. Used everywhere. I worked at petsmart last year and every day we had to had cups of this salt to the sump pumps for the freshwater fish. Trust me you to don't know what your talking about, it's a common method of reducing stress from fish and keeping them healthy. You have the right to your opinions, wrong or not.

Again, in specific cases over the short term adding salt may have value. In aquarium shops, where a certain loss of fish is acceptable and no fish is in stock for very long, adding salt may give benefits. It has a marginally useful effect on the spread of parasites and fungus. But compared with UV filtration, quarantining, etc adding salt will be a trivial activity. It may help profitability a small amount, but at the cost of stressing livestock in the long term. But since the fish will hopefully be sold in a few weeks, this doesn't matter as the fish won't have a chance to be sickened by the salt. In the home aquarium, where even a neon tetra can expect to live for 4 years, and angelfish for 10-12 years, long-term exposure to salt can be a stress factor. At tiny doses, probably not a major factor, but still worth considering.

The reason shops across the US (and the UK) sell aquarium salt is because it is cheap to make, carries a whacking great profit margin, but plays on the tendency of people to buy cheap solutions to problems instead of expensive ones. People could have much better water quality and less disease by spending $300 on a bigger filter and a UV sterliser, but instead opt for the $3 box of salt that says it will deliver exactly the same benefits. If salt really was a wonder drug vets would recommend it all the time, but they don't. Public aquaria don't add salt to their tanks. No professional fishkeeping writer recommends it as a matter of course. Scientists working in labs don't add salt to freshwater tanks, and neither do fish farmers raising strictly freshwater fish. Wild fish don't swim into estuaries when they are feeling sick, and where freshwater fish do inhabit brackish waters they are invariably less successful there than they are in freshwater habitats.

Feel free to buy and use salt. At best, it's doing nothing, and worst harming your fish by a small amount that deaths probably come from other causes anyway. But me, I consider tonic salt simply one of the classic "snake oils" of the hobby.

Cheers, Neale

Edited by nmonks, 27 May 2007 - 10:14 PM.





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