SALT
MECHANISM OF ACTION:
Fish cells are saltier on the inside than the fresh water outside. When there is unequal concentrations of salts, the area with higher salts will lose salt to the area with lower salts. At the same time, water will move from the area of lower salts into the area of higher salts to dilute the salts. This is called osmosis. It is the reason that blood on clothes is removed by soaking in plain water ... it lyses the blood cells and dilutes the iron out of the cloth.
All animals that live in fresh water have to expend energy to hang onto their salts AND to keep the fresh water out. Most of the fresh water fish can no longer deal with "salt water" conditions (altho ocean going salmon can go back and forth from salt to fresh water).
But adding some salt to the tank water lowers this energy expenditure. Salt also does one other thing, it stimulates the production of slime. Fish dont have much in the way of antibody, but they do have a secretory kind that is added to the slime coat where it reacts with parasites. But having a continuous production of slime, parasites have a harder time getting to the skin of the fish and shedding of the slime coat sheds many of the parasites as well. Normally, healthy fish are resistant to even pathogenic strains of bacteria. However, fish suffering mechanical damage from handling or spawning that removes the slime coat and/or opens a wound, those that have a primary infestation with a parasite that opens the slime coat and punctures the skin of the fish and when water quality/oxygen levels/temperature are so poor that the immune system of the fish is dysfunctional or there are infected fish shedding large numbers of bacteria in the pond can result in bacterial infection.
What salt dips do:
1. Helps fish that have been shipped recover their electrolytes
2. Strip off the slime coat and chemically knock off a lot of parasites.. it seems to be more of a shock to parasites than the fish
3. A fish that has been dipped is more susceptible to medications once the slime coat protectant is gone AND the remaining parasites are exposed to medications.
What low concentrations of salt does:
1. Provide needed minerals (if solar salt is used)
2. Stimulates slime coat production. Fish have antibodies and other anti microbial agents which are excreted into the slime coat where they bind to parasites.
3. Appears to protect fish against nitrite poisoning
CONCENTRATIONS:
Percent (%) is a measure of the number of grams of a chemical per 100 ml of water. So 0.3% salt solution means there is 0.3 grams of salt per 100 ml of water.
THIS HAS NOTHING TO DO WITH WHAT IS READ ON A SALT METER - please read the instruction manual that comes with the meter to translate what the METER says with what the concentration is in percent (%)
A solution of one teaspoon per gallon is 0.132% salt. So 1 tablespoon per 5 gallons is around 0.1%
A LOW concentration is up to 0.1%. This concentration will not hurt most plants and is what is typically used in ponds and tanks. Addition to fresh water is done over 3 days.
A MEDIUM concentration is up to 0.5% . Addition from 0.1% up to 0.5% should be done over a couple of days.
HIGH concentrations are up to 0.9% which is isotonic or the concentration within the fish. This concentration is used for medical reasons for very short baths. THIS CONCENTRATION CAN BE DEADLY TO FISH.
mild nitrite protection = 0.1% (3/4 teaspoon per US gallon)
preventive and nitrite protection = 0.3 % (2 1/2 teaspoons/gallon)
What kind of salt
Noga recommends "solar" salt WITHOUT ANTI-CAKING additives. The additive is sodium ferrocyanide (yellow prussiate of soda) which makes hydrogen cyanide when exposed to fish. On the topic of salt, p. 295 talks about salt dips for treatment of ecoparasites, columnaris and bacterial gill disease, and how salt dips remove the excess mucus making medications more effective against pathogens. Solar salt can be bought in food stores, in crystal form, no additives for water softening in big bags for cheap. Rock salt dissolves slowly. This means it will not flash burn the gills or skin like adding finely crushed table salt will. Almost all GF books specifically say no iodine.
SALT DIPS
Dips are brief exposures of a fish to a medication followed by the fish being put into fresh water.
Indications:
flashing or flicking
coming out of the summer pond and into an aquarium
the fish just arrived in a box or just brought home from the store
the fish isn't looking "well" or hasn't responded to topical treatments for
"fin rot or dots"
under a microscope, parasites are seen in substantial numbers
the fish has a resistant case of fin rot
Contraindications:
The fish are very small or fry ****** see caution
The fish have never been in "salted water" (like Israeli koi or shubunkins)
The fish is very toxed out from ammonia or other toxins (gills are dark red
or bloody looking)
Materials:
1/2 cup salt with no additives per gallon of tank water (no temp shock)
Methods:
0. mix the salt into the water.
1. put the fish into the salt water and start timing the dip. A salt dip of 30 seconds for small or stressed fish is sufficient. Fish can be dipped up to 5 minute if they continue to swim without sign of distress.
2. the fish will come up to the top, generally on its side, poke the fish and the fish will dive and swim
3. if the fish doesn't dive or doesn't dive quickly, take the fish out and put them into fresh water. It is not a good idea to put the fish back into the tank they came from until that tank is cleaned out or treated first for parasites.
4. take even a still active fish out after 5 minutes, leaving them in the salt dip longer will kill them.
5. for SMALL FISH, when they come up to the top and start rolling even slightly, they must be removed immediately no matter what the time limit. This means their gills can't handle it. Even if it has only been a few seconds.
Cautions:
1. the fish may dive to the bottom of the tank and sit there, this is usual
2. after the dip, the fish will "purge" both feces and ammonia from the gills, so the water must be tested and the water changed
