Re: [RML] rainbowfish goiter

Mach Fukada (fukada at
Tue, 24 Jul 2001 12:27:55 -1000

That jogged my memory.
I recall having goiters on Ps. cyanodorsalis. It was more frequent when
I would cheat and use less of the seawater mix and more evaporated coarse

----- Original Message -----
From: "Bruce Hansen" <bruceh at>
To: <rainbowfish at>
Sent: Tuesday, July 24, 2001 10:00 AM
Subject: Re: [RML] rainbowfish goiter

> I think you are right Tyrone , in that Iodine generally is found as a
> element in most environments and that there are very few areas in the
> where there is so little of it that deficiency states (causing goitre) can
> develop. My understanding is that Iodine is a necessary component of
> Thyroxine and other Thyroid hormones which animals produce to control
> metabolic rates.
> If the animals receptors detect a deficiency of Thyroid hormones then a
> feedback reflex stimulates the Pituitary gland to produce Thyroid
> Stimulating Hormone which then normally increases the production of
> Thyroxine etc.During the process each cell may increase slightly in size.
> If this fails to increase the availability of Thyroxines then the
> amounts of TSH cause the Thyroid gland to produce more thyroid cells which
> then increases the bulk of the Thyroid gland and it becomes visually
> and is then called a "goitre".
> I am not sure whether supplying iodine will totally reduce the size of the
> goitre until it is no longer obvious. However it should restore the
> metabolism of the fish to normal and allow them to feel well again. The
> important thing to remember is that raising fry in your iodine-deficient
> conditions needs to be allowed for.
> One of the things we forget when we raise fry in small volumes of water as
> compared to nature is that the rapidly growing animals use up minerals and
> nutrients from the limited volume we supply them with. If any element is
> limited supply then deficiency states may result - this goes for trace
> elements especially and perhaps adding a small amount of marine trace
> element drops regularly may help. In nature , even in very low TDS waters
> the water movement, and the sheer volume not only provides supply but also
> removes metabolites which may act as growth retardants.
> Bottom line message - perhaps some shell grit in each fry tank, frequent
> small water changes, and perhaps trace element supplements ?
> Regards,
> Bruce ( Hansen )
> vicepresident - ANGFA Inc (
> - ANGFA (Qld) Inc (
> ----- Original Message -----
> From: "Tyrone Genade" <Tgenade at>
> To: <rainbowfish at>
> Sent: Monday, July 23, 2001 8:09 PM
> Subject: Re: [RML] rainbowfish goiter
> >
> > I don't use an iodine mix or any salt mix with my
> > Tanganyikans. All I know is that of all the 'bows I've
> > raised in the tank so far none have developed any goiter
> > etc... No doubt there are iodine traces in the shell
> > gritt etc...
> >