# Is Iodine necessary?



## Edward

Hi

After reading few shrimp forums, I am not sure what the true about dosing Iodine is. Some say dose, some say don't. 
This shrimp forum says _.... Iodine is useless for fresh water shrimp._
Can somebody clarify this issue?

Thank you
Edward


----------



## Praxx42

I'll say this: Since I started using kent Reef Iodine at 1/8th strength, I have not had a single shrimp death except for "jumpers." I have amanos ranging from 1" to 3", and they all molt and spawn with amazing regularity. I have also used Iodine with larger FW shrimp, like Macrobrahim Lahs, and it kept them growing, molting and spawning quite well. The best example went from 7" to just over a foot long (not counting the claws) within 6 months.

Iodine won't hurt your plants or other livestock. It keeps you from having to isolate your shrimp to feed them iodine-laced foods for the molting process. And iodine is used by most large LFS service departments for their SW shrimp, why wouldn't the process be the same for FW shrimp?

Although this is just my opinion (both as a hobbist and a professional aquarium service technician), it comes from 2+ years of having used iodine as a tool , and a very successful one at that.


----------



## bharada

I've never dosed iodine and have a Cherry Shrimp population that is exploding in three tanks. That said, I haven't had the same success keeping (not breeding) Amanos. In my 40g tank I started off with 12, but now have none. In my 125 I have 2 out of 12, but most of the losses in that tank were the result of a CO2 mishap last year (lost a lot of Bee shrimp as well).


----------



## Piscesgirl

I use it and recommend it, but there are those who argue either side strongly. I would err on the side of caution, however, and not overdose. One drop her ten gallons, weekly should be enough. Do realize that some trace ferts also have iodide in them. 

I've learned to be a little less vehement in my discussions online as of late; But, I do remember countering someone who stated that we don't throw iodide into freshwater streams for shrimp and they do fine by saying we don't throw fertilizers into streams and the plants do fine as well!


----------



## Cavan Allen

I have rednose, 6 Amanos (2 females carrying now), and tons of cherry reds. I don't add any iodine.


----------



## richy

there isn't any conclusive *scientific* evidence that iodine is beneficial nor harmful to FW shrimp. there are those that argue why add if it's not necessary and those that argue why not if it isn't harmful. those are the most common arguments. most of what is out there is anecdotal evidence that adding iodine does wonders. i don't have any opinion on either argument, but i do add it weekly in case there are hidden benefits that i'm not aware of.


----------



## chiahead

from what I understand and I am no expert is that the shrimp need iodine in some form or another for there health. Most get it from the food that they consume but if they dont get it from their food supplimenting it will benefit there health. I read this in a few places although I cannot confirm wether it is true or not.


----------



## gnatster

Adding 1 drop in 10 gal is not going to hurt.

However iodine is quite reactive and it breaks down very fast so 1 drop once a week per 10 gal is seemingly going to do nothing. I know first hand that crustacean shells, shrimp, crabs, lobsters, all have iodine in them. Being allergic to iodine I find if I shell raw shrimp or lobster I break out in hives, pointing to high iodine content in the shell. 

Whats my point...

Adding iodine in the amounts we currently do is not going to harm anything and it may help. How can we can we put this theory to test?


----------



## Piscesgirl

Nori is a good way of providing the shrimp with all the iodide they need, although I still do add it to the water columb as well.


----------



## trenac

In the beginning I did not add iodine to my shrimp tank, but on the advice of PG I started when I had baby Cherry's and have continued to use it ever since. However I cannot tell a difference in my shrimp since using iodine and when I did not use iodine. However, I continue to use iodine in case it is doing something beneficial that is not visible to the naked eye. If using 1 drop per 10 gallons once per week does not harm the shrimp I see no reason not to use the iodine.


----------



## Veneer

> However iodine is quite reactive and it breaks down very fast so 1 drop once a week per 10 gal is seemingly going to do nothing. I know first hand that crustacean shells, shrimp, crabs, lobsters, all have iodine in them. Being allergic to iodine I find if I shell raw shrimp or lobster I break out in hives, pointing to high iodine content in the shell.


Just a note - the freshwater prawn _Macrobrachium rosenbergii_ has been confirmed to contain, by some nutritional studies, only 14-17% the iodine content of comparable marine Penaeids; individuals allergic to iodine are thus, in many cases, able to safely consume them. Industrial-scale aquaculture facilities do not dose aqueous iodine (though diet perhaps satisfies this supposed metabolic requirement) and yet still rear and breed _M. rosenbergii_ on truly massive scales.



> But, I do remember countering someone who stated that we don't throw iodide into freshwater streams for shrimp and they do fine by saying we don't throw fertilizers into streams and the plants do fine as well!


Then again, streams are readily supplied with minerals, decaying organics, and the metabolic byproducts of the biota therein, whereas iodine is present in such negligible quantities as to necessitate (without alternate sources), in many cases, external supplementation, even where local water and regionally-grown crops are ingested.

To my knowledge, the scientific literature has considered iodine requirement as regards shrimp only in terms of a dietary prerequisite; there is no empirical evidence to suggest that freshwater shrimp are even capable of absorbing iodine from the water column.

Some articles (general information on iodine supplements; their potential utilization by [marine] shrimp [I found effectively no websites that backed up speculation on freshwater iodine supplementation with quantifiable scientific support]; the biochemistry of molting in freshwater shrimp; trace element utilization by various crustacea; the endocrinology of molting in freshwater shrimp; etc.), divided among web pages, "white paper" abstacts, and aquaculture reports:

Chemistry and the Aquarium (one section is specifically devoted to shrimp):



> Who uses iodine: Shrimp
> 
> As one moves up the food chain to more sophisticated organisms, data on their ability to take up iodine from the water column becomes very sparse. Shrimp are known to have a need for iodine to grow, but that is only known in terms of a dietary requirement. The shrimp, Penaeus chinensis O'sbeck, for example, grows optimally when the diet contains 0.003% iodine.56
> 
> Shrimp apparently incorporate substantial amounts of iodoorganics into their bodies. The shrimp Pandalus borealis, for example, incorporates between 0.04 and 2 ppm iodine as iodoorganic compounds depending on the particular body tissues examined. Their roe were somewhat higher, up to 4 ppm iodine as iodoorganic compounds.57 Shrimp shells and other parts can contain up to 17 ppm by dry weight iodine, the majority of which is iodoorganic compounds58, but the values are still far lower than for other inverts like macroalgae, sponges, or gorgonia.
> 
> Still, the amount contained says nothing about whether iodine is an important requirement. I could find no scientific studies that showed that shrimp need iodine from the water column, but neither could I find any that demonstrates that they do not.


An Iodine Supplement FAQ from WetWebMedia.

A discussion of iodine supplementations with some intriguing commentary concerning crustacean molting:

(An excerpt):



> Ron Shimek wrote in last months FAMA that Iodide is poison and is dangerous to use. He stated there is not scientific proof that Iodide is even used by corals and that hobbiest [sic] test kits and [sic] not accurate and you can not [sic] maintain levels equivalant to the sea by use of these kits.


Investigating the Composition of the Exoskeleton of _Macrobrachium rosenbergii_ - an inquiry into the particulars of this freshwater prawn's molting cycle.

Stable Amorphous Calcium Carbonate Is the Main Component of the Calcium Storage Structures of the Crustacean _Orchestia cavimana_ - though this study centered about a terrestrial organism, the points made about biominerals, ion reservoirs, and calcium storage strategies should remain in broader consideration.



> One of the carbohydrates that shrimp meet in natural environment might be chitin. And the question was raised [sic] is the chitin used by shrimp better than other CBH? Chitinase activity was measured in a 332 number of species and bacteria living in the gut showed chitinolytic activity for a number of species too. Gwinn and Stevenson (1973) have speculated that in Orconectes limosus, the major energy source is chitin, because chitin resorbed by the hypodermis before molting provides sufficient material for
> both new chitin synthesis and energy for molting (1.4 kJ which represents around 25% of energy accumulated in intermolt period).
> 
> Chitin
> 
> Chitin digestion and assimilation occur and make a significant nutritional contribution to shrimp (Clark et al. 1993). Shrimps reared under experimental conditions tend to ingest exuvia of newly molted shrimp with a kind of avidity, which seems to be in relation to the fact that a diet is well-balanced or not. Some diets containing shrimp meal showed poor growth performance and glucosamine could have a beneficial action a new exoskeleton synthesis (Kitabayashi et al. 1971) even though the levels tested (0.5-0.8%) represent a small percentage. Dietary supplies of glucosamine could be insignificant
> compared to the metabolic supply provided that a substantial amount of glucose be available ammonioemia in hemolymph is given to be high (1.6-1.9 mg/ 100 cc in the blood of lobster or crayfish; Florkin, 1966). However, Ross Stevenson (1983) mentioned a pathway for glucosamine involved G6-P
> and F1-P. And this is contrast with the fact that glucose phosphorylation capacity of shrimp is low (probably less that in fish) and most likely, metabolism of glucose is poor in comparison to mammals.
> In fishes, level of chitinase in blood and lymphomyeloid tissues is suppressor to the one in gastrointestinal tract [sic], indicating a diffusion role rather than a digestive capability for chitin. In shrimp such a statement do [sic] not apply.
> 
> Chitin synthesis in shrimp cannot be considered out of the molting cycle, which shows the evolution of organic reserves in the digestion gland. Renaud (1949) clearly demonstrated in crabs the variation in glycogen. Also Cuzon (1976) reported this in M. japonicus, and again glycogen in hypodermis, which
> indicates an intense metabolic activity including important transport of nutrients from an organ to another, starting in stage C of the intermolt period and in preparation to the next molt. Such transfer [sic] imply hemolymph which dispatch nutrients to different tissues in which metabolism will be oriented according to a given period of the molt cycle.


(From http://www.uanl.mx/publicaciones/maricultura/acuiculturaV/gcuzon.pdf)

I do not deny that iodine is necessary, in trace quantities (as obtained via foodstuffs), for freshwater shrimp; the potential endocrinological effect of iodine metabolization is, to my knowledge, an uninvestigated branch of inquiry:



> Artificial production techniques are based on the ability to induce reproduction and spawning in captivity, but knowledge concerning the basic mechanisms of these physiological processes is insufficient. In this research, the involvement of various endocrinological factors in the control of molting and reproduction were investigated in M. rosenbergii. Ecdysteroids which control molting, were additionally found to accumulate in maturing ovaries and to be present in newly-laid eggs, indicating a potential role in ovarian development and embryogenesis in this species. In addition, juvenile hormone (JH)-related substances were investigated, revealing the presence of the JH precursor, methyl farnesoate (MF) in the hemolymph. (MF) was seen to fluctuate during the molting cycle, suggesting that this hormone has a role in molting in addition to reproduction.


(From http://ss.jircas.affrc.go.jp/kanko/seika/seikah8/4-13.html)

Continuing along this track of thought, "liquid iodine" supplements' alleged effects on shrimp molting (if, in fact, valid) may come through interference with "molting" and "molt-inhibiting" hormones:



> In M. rosenbergii and most other species of decapod crustacea including crabs and lobsters, the physiological processes of molting and reproduction are inextricably linked and under the control of various hormones. Crustaceans, which are arthropods, bear much endocrinological similarity to insects, and differ greatly from vertebrate species. However, compared with insects, which have been studied more widely, little is known about endocrinological mechanisms in Crustacea.
> 
> It is well-established that ecdysteroids such as 20-hydroxyecdysone serve as "molting hormone* in Crustacea and are excreted from a tissue known as the Y-organ. On the other hand, peptides (molt-inhibiting hormone: MIH) originating in the sinus gland complex of the eyestalks exert negative influence on molting. In M. rosenbergii, molting occurs approximately once per month accompanied by growth of the animal. In females, reproduction occurs in synchronization with the molt cycle during which vitellogenin (yolk protein) is produced and ovaries develop and mature. This process is also under the inhibition of an eyestalk hormone: vitellogenesis-inhibiting hormone (VIH). In hatcheries and on prawn farms, the technique of eyestalk ablation has long been employed to induce female maturation; the basis of this is the removal of the eyestalks and thus the removal of the source of these inhibitory hormones.
> 
> While much progress has been made regarding negative control of molting and reproduction, it is unclear whether positive control mechanisms exist. Regarding molting, it is still not known what causes ecdysteroid titers in the hemolymph (crustacean blood) to surge just before a molt. It is also not known how the negative effects of VIH are lifted, enabling the animal to produce vitellogenin for uptake into the ovaries. In insects, juvenile hormone (JH), which is a larval developmental hormone, also appears in the adult female to stimulate yolk protein production and uptake. At JIRCAS, we are interested in the functioning of juvenoid substances in M. rosenbergii and are attepting to determine whether such hormones exert similar influences in crustacean species. At present, we have detected a JH-precursor molecule, methyl farnesoate (MF) (Figures 2a,b), in the hemolymph of M. rosenbergii. It was expected that MF would be present in only females undergoing ovarian maturation, but it was detectable in both females and males without connection to reproductive events. MF was also seen to fluctuate during the molting cycle, suggesting involvement together with ecdysteroids in regulating molting.


(From Molting and reproduction in the giant freshwater prawn, Macrobrachium rosenbergii: Endocrinology and potential aquaculture applications)


----------



## Piscesgirl

Wow, thank you for that information, Veneer.


----------



## johnzimm

bharada said:


> I haven't had the same success keeping (not breeding) Amanos.


I have heard that Amonos will not breed unless they are in brackish water.


----------



## DutchMuch

johnzimm said:


> I have heard that Amonos will not breed unless they are in brackish water.


They breed in Freshwater.
But the fry wont live in Freshwater. 
They need brackish.


----------



## johnzimm

DutchMuch said:


> They breed in Freshwater.
> But the fry wont live in Freshwater.
> They need brackish.


Good to know, thanks for clarifying that.


----------

