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Hi all! Newbie here...
I've recently been hired at a pet store with a reasonable sized fish section, and while I have a zoology degree, I'm finding the learning curve of fish to be rather steep (My expertise is lizards and turtles). I'm technically being trained as the new "fish" person, to free up time for the current fish person, as their also the manager. So I'm glad I found this place to ask my questions!
First question.... when I clean tanks every week, I'm putting in salt too, as per instructions from current fish person. I'm putting in approx. 1 tsp/5 gallons changed. Why am I doing this? What exactly is the salt doing to help the fish? Is this the correct amount? This is what I'm adding to the goldfish, tetra community and livebearer sections. The cichlids get their own cichlid water conditioner. The other sections are also getting Prime and Cycle, and I understand what these two are for, but the salt confuses me.
Thanks for any insight!
Littlesmit

Hey, welcome to the site

You are doing it because it is the 'done thing'. Most times when people dose this, the idea behind it (as far as I can figure anyway) is to push the salinity to a point that the fish can cope with, but the pathogens can't. The pathogens haven't got the memo. With some things it seems to have a small effect, but overall it isn't all that helpful. It is a bit of an old practice, but people still use it. In some cases they swear by it, in others they don't notice a difference. It could be something to do with the difference in water supply, or the fish they keep, or just what they perceive to be true. Hard to say, but generally it is now accepted that it isn't all that helpful.

The time when it is helpful is if your tank is cycling and you want to prevent the uptake of nitrate. I'm not certain of the exact action, but it has to do with body cells being fairly non-selective when looking for chloride ions and picking up nitrite ions instead, causing the whole methaemoglobin mess and possibly death. When you increase the salt in this situation, you increase the chance that the fish's body is going to pick up a chloride ion, reducing the effect of the nitrite by kind of out-competing it. That is when salt is very useful. Given you are dosing with prime and cycle at each change, I can't see that you'd be getting a particularly big nitrite spike.

It can also be quite problematic as freshwater fish bodies are designed for low salt concentrations in the water and their osmotic regulation is geared to cope with that. If you overload the environment with salt then you can end up putting extra stress on the fish's body.

For animals, the entire universe has been neatly divided into things to (a) mate with, (b) eat, (c) run away from, and (d) rocks. - Terry Pratchett

Well that answers my question more than I expected! Thanks!

Will this added salt, over time, hurt the fish? Should I be trying to convince the current fish person to perhaps stop? Is there an article I can point her way about this, or is this, like most of this hobby, found out by trial and error, and person preference?

What about specific fish? I add double this amount to the tanks with platys and glass catfish, which are brackish... right? does that mean other livebearers are more tolerable to this salt?

i've also had customers who have claimed to use ordinary table salt as their aquarium salt... am I correct in assuming the added iodine isn't totally great in an aquarium? One lady today completely insisted that our store has told her time and time again that table salt is fine, and much cheaper... but I don't feel thats right.

Thanks again for your help!

Hi,
Years, in fact, decades ago, salt was added to the water
as a sort of "preventative" so that the fish might not
catch Ich (a parasite). When you add salt to the water
you increase the metabolism of the fish and this in turn
causes stress, which in turn causes the fish to produce
more of the mucus coating that covers all fish.

The thought was that if the coating was thicker, and it
was produced faster, that it would prevent the parasite
from attaching itself to the host.
Today much more is known about the life cycle of the
parasite and "we" have perfected medications that can be
used to treat for outbreaks of the parasite.
These medications are easily obtained at any LFS, are
inexpensive, and very effective.

Decades ago many of our fish were "wild caught" and some
of them, such as mollies, required salt be added to their
water for good health. Today we have very few of those
fish that are wild caught. Instead, they are farmed, many
of them in Florida and other Southern States as well as
overseas and shipped in. The result is that those fish
no longer require the salt as they are many generations
removed from their homes.

Some folks who specialize in live bearers, add salt because
it can enhance the natural colors of the fish.

The salt that is used is salt without Iodine. At one time
all our salt had no iodine, then the health department
decreed that "we" needed iodine in our systems and that
the population was not getting enough and so we now have
iodized salt. Appreciable quantities of iodine are not
good for fish. While the popular shrimp of today actually
do require some iodine in their diets, the bottles of
iodine sold for shrimp care are very specific about not
exceeding the recommended dosages and cautions about using
iodine with certain fish.

Use only Kosher Salt off the shelves, or use salt
specifically sold by your LFS for aquarium use. One should
not use iodized salt for aquariums.

One of the problems with using salt is, well, people.
Many, especially folks new to the hobby, do not
realize that salt does not evaporate from the tank
along with the water. Thus, when they replace the
water (top off the tank) with fresh water, they add
more salt. Eventually the amount of dissolved salt
exceeds what the fish can tolerate and they loose
what are usually the more expensive fish first.

In summary, the use of salt in a freshwater tank
as a prophylactic is no longer necessary or even
advised.

Here is an article about salt in the freshwater aquarium:
http://oxyedge-chum.com/oxygen_or_salt.htm

Frank



-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Frank You bring back memories of when I first started salt was a must in those days especially with live bearers.

As a matter of fact the only salt in the house today is a good Sea Salt for cooking.

Have a look in [link=My Profile] http://www.fishprofiles.com/forums/member.aspx?id=1935[/link] for my tank info

Look here for my
Betta 11Gal Desktop & Placidity 5ft Community Tank Photos

Keith

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Will this added salt, over time, hurt the fish? Should I be trying to convince the current fish person to perhaps stop? Is there an article I can point her way about this, or is this, like most of this hobby, found out by trial and error, and person preference?

Probably not, if you make sure that you only replace what you physically remove. If you keep most things to do with water chemistry constant then it should be less stressful on the fish, however you are usually only a 2 week stopover for the fish, and most likely the farmers, shippers and wholesalers don't salt their water. IMO it'd be better without, but if it is going to get the boss in a tizz then it isn't really something that will cause massive damage, especially in the systems that you are using it in.

What about specific fish? I add double this amount to the tanks with platys and glass catfish, which are brackish... right? does that mean other livebearers are more tolerable to this salt?

There is a difference between brackish and salt-tolerant. Platies, mollies, guppies and swords, those core livebearers that you normally find at pet shops are salt tolerant, not brackish. They don't need or like salt but they'll cope better than other fish (especially mollies, which can tolerate full brackish or even full salt, but seeing as yours will have been tank-raised in fresh and will be destined for fresh that is not really advisable to attempt anything like that in a retail setting - just be aware that it might come up as a point of discussion should you suggest removing the salt from the system). I wouldn't have classed the glass cats or tetras as salt-tolerant to any great degree, so I'd be considering cutting the salt addition down or out on those tanks, if you can. On one hand I can understand why, going by the old reasoning, someone would feel it prudent to add salt to those tanks given the delicate nature of the tank-bred specimens, but yeah, not what their bodies are designed for.

i've also had customers who have claimed to use ordinary table salt as their aquarium salt... am I correct in assuming the added iodine isn't totally great in an aquarium? One lady today completely insisted that our store has told her time and time again that table salt is fine, and much cheaper... but I don't feel thats right.

In the quantities that most people will use, even iodine and anti-caking agent shouldn't cause massive damage, but I wouldn't advise using anything other than pure salt if store policy is to advise the use of grocery-store salt in freshwater (if you can get away with not recommending salt at all, all the better). Kosher salt would be best of the grocery store types, as frank said, and for ease of dosing I'd suggest rock salt over table salt. The reason is that most people want to dose for volume, not weight. The quantity of table salt per teaspoon is more than the quantity of rock salt, and almost all dosages in books and online that are based on volume are based on rock salt. It is a small difference, but I find it makes a difference (plus there is less chance of there being additives in rock salt, so an extra bonus there)

For animals, the entire universe has been neatly divided into things to (a) mate with, (b) eat, (c) run away from, and (d) rocks. - Terry Pratchett

Ah, it's time for this dissertation again.

There is an important distinction to be learned here, between primary freshwater fishes and secondary freshwater fishes.

A primary freshwater fish is one that has never had any marine ancestors in its entire evolutionary history, stretching way back to the Devonian era and beyond. Fishes in this category have never evolved the osmoregulatory machinery to handle salt in the water, and so exposing a primary freshwater fish to even a small amount of salt is likely to do more harm than good.

An important group of aquarium fishes falls into this category, namely the Ostariophysans. These fishes are so called because under an older taxonomic scheme, they were placed in the Order Ostariophysi, and were characterised anatomically by the presence of a collection of bones connecting the swim bladder to the inner ear, known as the Weberian Ossicles. Under the modern taxonomic scheme, the Ostariophysi is a superorder, and the members have been assigned their own orders. The principal ones of interest are:

Order Characiformes - Characins and allies
Order Cypriniformes - Carps and allies (including Loaches)
Order Gymnotiformes - Gymnotid Eels (which resemble Knife Fishes)
Order Siluriformes - Catfishes

There are a small number of exceptions to the rule that Ostariophysans are all freshwater - the two important ones being the Family Plotosidae (a Family of true marine Catfishes) and the Family Ariidae (a Family of Catfishes whose species move between fresh and brackish water). Apart from those important exceptions, ALL the other Ostariophysans are primary freshwater fishes, and should never be exposed to salt. Even short-term exposure as a temporary treatment for various ailments in lieu of modern fish medicines is likely to have a negative effect, particularly with Catfishes - Corydoras and the like should NEVER, EVER be allowed to even sniff a single grain of salt if you want to keep them healthy and happy. The rule is particularly important for those fishes that live naturally in soft, acidic waters such as the Amazon, which are not only completely free of any salt content whatsoever, but which possess very low concentrations of other dissolved minerals. Consequently, salt is ruled out full stop for Amazonian fishes, and especially Ostariophysan fishes. Salt is also ruled out for all other familiar Ostariophysans - Carps (that's Rasboras, Danios, Barbs, Red Tailed Black Sharks, Siamese Algae Eaters et al) and Loaches (Kuhlii Loaches and Botia type Loaches in particular, though it applies right across the board with any Loach type fish, including members of the Balitoridae and Gyrinochelidae).

Right, that's primary freshwater fishes covered.

A secondary freshwater fish is one that did possess marine ancestors somewhere along its evolutionary history, and the more recently this occurred, the more salt tolerant such fishes will be. The classic example of secondary freshwater fishes is the Cichlids - these shared a common ancestor with a range of other Labroid fishes including the Damselfishes of the Family Pomacentridae, the Wrasses (Labridae) and a range of others. The phylogeny of this group is complicated, so I won't cover it in detail here, but suffice it to say that Cichlids still retain some osmoregulatory capacity to handle salt in the water. Indeed, the Asian Cichlid Genus Etroplus (the only Asian Cichlid Genus in existence) is comprised principally of brackish water fishes. Many of the truly freshwater Cichlids (particularly African Rift Lake Cichlids) live in heavily mineralised waters in the wild, and their osmoregulatory machinery has evolved over time to cope with high mineral concentrations. Even with these fishes, however, salt is NOT necessary (with the exception of the brackish species cited above) and if these fishes are in a community setting alongside ANY primary freshwater fishes, then again, salt is to be avoided.

The Poeciliid livebearers are interesting in that several species are truly brackish, and one species in particular, the Giant Sailfin Molly, Poecilia velifera, is fully euryhaline, being capable of migrating between freshwater and fully marine environments. Indeed, it is possible to go diving off the Yucatan and find Poecilia velifera in the wild in a coral reef setting! However, if your specimens are aquarium bred, and have been raised in fresh water, chances are they will require very slow acclimatisation to anything other than a modest salt concentration (i.e., anything above 5% marine strength). However, Poecilia velifera (the true wild strain, as opposed to the numerous 'velifera hybrids' with fancy finnage such as lyre tails) seems to sparkle and really come into its own in a brackish setting, and for this particular Poecillid livebearer, I would recommend either hard, alkaline fresh water or 5% marine strength brackish water for optimum health, along with relatively high temperatures (velifera Mollies are particularly e to "shimmies" if subjected to sudden temperature drops) and a lush algal growth for grazing.

Some Killifishes are also brackish water fishes - check each species individually, take note of those that can be found in a brackish environment in the wild, and adopt appropriate care and management strategies when you alight upon a species that fares best in a brackish setting. Needless to say, Cyprinodontiform fishes (Killies, Poeciliid livebearers etc) are also secondary freshwater fishes.

Fishes that should have some salt content in the water - varying according to species - include true brackish water fishes such as numerous Puffer Fishes (some of these require increasing salt concentration with age, again check individual species to determine which fall into this category), Archer Fishes, Monos, Scats and Bumblebee Gobies. These are fishes that should have 5% marine strength water for maintenance as a minimum, in some cases 10%, and in the case of those Puffer Fishes that migrate in the wild to increasingly marine-strength habitats, provision should be made to house them in a species aquarium and provide them with slowly increasing salt content over a 5-year period.

A complete list of fishes that breaks them down into primary and secondary freshwater categories would fill a book, and I think Adam might object to me posting a single post comprising several megabytes of text on his server!


Panda Catfish fan and keeper/breeder since Christmas 2002

Lovely post there calilasseia, saved me a lot of trouble lol.

A blanket approach in any fish shop that involves adding salt to freshwater species is ridiculous and counterproductive. Petition for the reversal of the policy.

It was probably only started by some nitwit with at best a partial knowledge of fishkeeping, and none at all about the properties of salt and its effects of freshwater fish. Such figures often become almost legendary in status, often in their absence, and those who keep espousing the practise in succession usually showing needless mental inflexibility.

Do what you can to change this stupid blanket approach to water chemistry. It will harm more fish than it helps.


In my last job it was one of the first things I changed, along with correcting the water change practises, and combined the two new procedures (really only standard good fishkeeping) dropped a monthly death rate from 20% to 2%. It took two months to see the benefit. In literal terms it saved approximately 80 fish a month. When people are insistant about archaic practises they really have no notion of the damage they are doing. Perhaps print this off and show it to them.

Should they need a reminder of good water quality control principles in a commercial environment, Im quite capable of updating them. Just get them to mail me.

Just wanted to say a large thanks to everyone who replied Each answer was extremely informative and helpful, and I now feel ready to present the info to the current fish person (she hasn't been in in a few days). She is, in all other fish practices, and from what I can tell, very well informed and manages her fish tanks well. There is very little die-off excepting the feeder goldfish tanks, and all her practices seem to be good standard.
I'm also very glad to have found a forum where the inhabitants are so knowledgeable and welcoming!
Cheers to all!