the effects of iodine on crustacean molts

[justinl]

The question of molting seems to be a funny thing. There is a rumour flying around here and there that addtions of iodine help a molt. Dr. Roy, I know you've already mentioned that it doesn't help but actually forces a molt.

I did my own little scholarly search at my university but found little to do with the effects of iodine and crustacean molts, and pretty much all of what I found had to do with studies on FW organisms. Applying FW logic/studies to SW can be a dangerous thing IMO.

The reason I bring it up is that I would like to hear others' opinions on this, especially yours, Dr. Roy. I was also wondering if you could search a little on this seeing as you would have greater access than me (student) to info and let us know what you find. It would be greatly appreciated and would clear a lot of smoke about the issue.

 

[Frozen Roadkill]

My brother had a peacock mantis, and added iodine a lot. We believe it killed the mantis, cause after so much heafty iodine dosing, the mantis' next molt went way wrong and she died.

 

[Pea-brain]

I think that mantises get more than enough iodine in their diet. Though I would like to know if a mantis is having a bad molt, would a dose of iodine help? just a thought.

 

[mattyice]

well if it does indeed force a molt then i could see it helping a failed molt in the last few stages, but only if the animal is showing signs of molting...ex. closing up for a long period of time to molt, and coming out without a new molt...i believe in that case that the animal has a new shell growing under its old one but its just not able get its old molt to release

 

[Pea-brain]

Another thought: maybe use in emergency cases of life threatening shell disease? It would be risky, but faced with certain death maybe......

 

[mattyice]

the only reason i could see using it is in the case of a failed molt

 

[Gonodactylus]

I have asked contributers every time I 've seen them say that iodine helps stomatopods molt where they got their information. So far, no one has cited any research on stomoatpod and I doubt that any exists. Also, I have never said that that iodine "forces the molt" in stomatopods. What I have said is that as long as the animal has a normal diet consisting of marine shell fish (shrimp, clams, krill, crabs, etc.) there should be no need to supplement the diet with iodine and given the toxic properties of iodine, attempts to do so could be lethal.

Roy

 

[mattyice]

i guess what im saying is that people say that other inverts have molted after dosing iodine to the tank, im just taking this info and maybe it could work with stomatopods, im not saying that it does but its worth a shot if you dose it in the corect amounts to the tank it could be enough to get a mantis shrimp to molt, im only saying to do this if the mantis closes up and there is a failed molt, im not saying it happens but if we could get enough examples of this then maybe it could prove that this could end failed molts in stomatopods and help their survival rate in captivity

 

[Gonodactylus]

The physiology of the molting process is complex and takes weeks for the animal to secrete the new skin, resorb vital nutrients, etc. Applying iodine at the last minute when things are going wrong sounds to me like a recipe for disaster. Anything that stresses the animal when it is attempting to molt is likely to have lethal consequences.

Roy

 

[mattyice]

well this would be after you know there is a failed molt, as they are out in the open and you can physically see them suffering, i doubt it would work but im saying there is more of a chance of the animal dieing when its like that then it surviving, so i feel it could be worth a try

 

[Gonodactylus]

A that point, a better and more humane solution is to put the animal in the freezer.

Roy

 

[mattyice]

oooo i really had no idea that iodine is that potent, if i would of known that i wouldnt of kept trying to make a big deal of it

 

[DanInSD]

Iodine is biologically very active (look at the USRDA for us -- 150 micrograms!). Most of us get all we need from a few grains of iodized salt.

Shrimp of most sorts have relatively high iodine/iodide concentrations. Dr. Roy has said multiple times that including shrimp in your mantis' diet is more than adequate to ensure ample iodine/iodide.

 

[Frozen Roadkill]

So it could have killed my brothers peacock?

 

[DanInSD]

Could? Yes. So could a bad powerhead or other electrical gizmo like a heater; random bad luck; insufficient filtration and/or water changes; excess salinity/temperature fluctuations; improper diet; exposure to environmental toxins; ...

A good mantra that I've heard, and now stick to, is only add what you can measure. My wife and I used to add vitamins, "Reef DNA" (?), iodine, strontium, all kinds of stuff to our reef tanks. One day, we just stopped, and everything has been as good or better. The only supplements we add are calcium/alkalinity two-part and the occasional bit of buffer. We use RO/DI water and Reef Crystals salt, doing 15-30% (depending on the size of the tank) biweekly water changes.