Liquid fish food salt problem?

[argonaut]

Hi,

there are many brands who sell liquid mysis, copepods and so on. I measured the salt content and it is about 12%, more than three times higher than seawater. Has anybody an idea if this could harm fish over time? Saltwater fish have to drink a lot because of the lower osmotic pressure in their bodies. So additional salty food my be a kind of stress for the fish and their organs.
The liquid food is sold as single feed with 1-2 portions/day.

 

[vaguelyreeflike]

I don’t think it should cause issues, but if worried just pour some into a container and dilute it with RO water before feeding. I thaw all my frozen foods in RO water as well

 

[argonaut]

yes, but I don't think that helps much. If you put something in a salt solution, it will relatively quickly have the same salt concentration as the surrounding water due to the osmotic pressure. In this respect, the mysis should also contain 12% salt after a while (in the body). Washing out only removes the surrounding water.

The background to this is that I would like to try making a DIY food. I want to pop up frozen food bars, mix them as required and put them in an approx. 12% salt solution. At this salt concentration, most bacteria and mold no longer grow.
This would then be a great food for vacation replacements and is also somewhat easier compared to frozen food.

As far as I have read, the various manufacturers do not use any preservatives, the salt solution should be sufficient.

However, there is a recommendation, for example, to soak nori algae in fresh water before feeding to give the fish an additional benefit. If you constantly feed food that has a considerably higher salt content, I don't know whether this is really good in the long term. The companies offer it this way, even as a single feed, 1-2 times a day. In this respect, it shouldn't be a problem. But it would be nice to know exactly.

 

[Mr. Mojo Rising]

I think you are overthinking. If this was a problem, we would have heard of it, but never ever have heard of concerns of additional salt in the saltwater fish food.

if anything, fish living in aquariums live longer than fish in the wild.

Or don't feed liquid mysis anymore, I never have and my fish have been with me for years.

 

[Nano_Man]

Simple if you think it’s raising salt levels don’t use it or only once a week that won’t make a difference . My fish drink a lot of vodka for my nitrate reducing they love it

 

[exnisstech]

Wow. I'm sorry it's all I could come up with as I never thought of or heard of someone measuring the salt content of fish food.

 

[vaguelyreeflike]

yes, but I don't think that helps much. If you put something in a salt solution, it will relatively quickly have the same salt concentration as the surrounding water due to the osmotic pressure. In this respect, the mysis should also contain 12% salt after a while (in the body). Washing out only removes the surrounding water.

The background to this is that I would like to try making a DIY food. I want to pop up frozen food bars, mix them as required and put them in an approx. 12% salt solution. At this salt concentration, most bacteria and mold no longer grow.
This would then be a great food for vacation replacements and is also somewhat easier compared to frozen food.

As far as I have read, the various manufacturers do not use any preservatives, the salt solution should be sufficient.

However, there is a recommendation, for example, to soak nori algae in fresh water before feeding to give the fish an additional benefit. If you constantly feed food that has a considerably higher salt content, I don't know whether this is really good in the long term. The companies offer it this way, even as a single feed, 1-2 times a day. In this respect, it shouldn't be a problem. But it would be nice to know exactly.

If you put the food in saltwater, this is true, but if you mix it into RO freshwater then it would dilute the salt content as the salt will leave the foods and mix into the water. I’ve never had any issues using RO with foods

I do agree this is very overthought though.

 

[argonaut]

Overthought, yes maybe.
Fish, like other organisms, have effective mechanisms for excreting salt. Too much salt leads to overloading of organs and the circulatory system in many organisms (including humans).
I am not indifferent to whether a fish with a life expectancy of 10 years only lives for 5 or 6 years just because it is poorly nourished.
And yes, there are of course all kinds of alternative foods, but I find the liquid form, whether mysis, krill, copepods or whatever, very convenient.
Of course you could rinse the whole thing in fresh water again, but the advantage of liquid feed is that it is very uncomplicated. Open the fridge, pump 3-4 doses into the tank - done. No rinsing, no fishy smelling hands when you put the frozen food cubes into the tank etc.
I think only a biologist will be able to answer this question, if at all.

 

[mfinn]

I think only a biologist will be able to answer this question, if at all.

Or maybe just common sense.
The amount of excess salt in the food is is just a tiny fraction when added to aquariums, and is diluted immediately.
Even in small tanks it's just a drop in the bucket.

Using these various foods, I have fish that are decades old as many others here have.

I too think you are overthinking this.

 

[Joe31415]

but the advantage of liquid feed is that it is very uncomplicated

You'd think, but here we are.