[RML] Re: Suitable hardness

Cary Hostrawser (caryho at ix.netcom.com)
Sun, 01 Dec 1996 15:42:56 GMT

On Sun, 01 Dec 1996 21:55:41 +1100, Andrew Boyd <andrew at pcug.org.au>

>At 06:40 PM 11/30/96 -0800, Greg Tong wrote:
>>I'll be setting up some tanks for my first foray into rainbowfish land. I
>>can adjust temp and pH (with a DIY yeast setup to generate CO2 for the
>>aquatic plants) but want to know about hardness. My water's dKh as measured
>>by the Sera test kit is 3.0.
>That's not too far off our local tapwater's hardness here in Canberra (ducks
>the inevitable chemistry lesson hurled at him! ;) ).
>>I'm looking into 1) I. werneri, 2) M. praecox, 3) peacock gudgeons (name?),
>>and 4) P. furcatus. Is my hardness suitable?
>The Peacock Gudgeon is Tateurndina occelicauda, and you should know that the
>werneri and the furcatus can be hard to keep alive.... Opinions vary wildly
>as to the suitable hardness for keeping all native fishes...
I think that's because Sahul fishes come from wildly varying water
conditions. What works for one species is a disaster for others.
People tend to call easy the species that do great in your local water
and call difficult the species that need a different water condition.
I on the other hand am forced to modify my tap water for almost all
fish to do well.

>>(BTW, I'm experienced keeping aquatic plants and using DIY CO2 setups. And
>>I will not be mixing the rainbowfish in one tank. I would like to keep the
>>gudgeons with one of the rainbowfishes ...)
>They should be fine with the praecox, I guess... The furcatus and werneri
>are a li'l more delicate and IMO should be kep in species tanks (not that I
>keep either, mind, I always kill the werneri I get, and I've never risked
>any of Australia's dwindling stocks of furcatus to my tender mercies ;) )
I agree with Andrew that the werneri should be kept in a species only
tank. They don't seem to compete for food very well with other fish.
They may be alright with the peacock gudgeons, because they generally
stay at the bottom and werneri are mid-water feeders. Actually I don't
see any reason you couldn't mix all these species with the exception
of the werneri. The furcatus prefer the top levels, praecox the mid
level and peacock gudgeon the bottom level. Also, since these fish
won't cross, you can harvest fry from the tank.

The furcatus are very easy fish to keep and spawn. I would qualify
that with one consideration, you must keep the pH up above 7. 7.0
being the danger point. Letting the water drop beneath 7.0 will wipe
out a colony extremely fast. I've done this on a couple of occasions.
With such a low dKH I would recommend adding some Baking Soda to the
furcatus tank if your pH isn't high enough to be safe. They'll do just
fine at a pH of 8 if you want to be doubly sure.

I've taken to adding the HBH Balance Blocks to all my rainbow tanks.
It did solve a problem that cropped up last summer (winter for you Oz
folks) of deformed fry fins. I believe the formulation of the
commercial acid I was using to drop my pH had changed causing the
problem. My tap water is GH 315 ppm, pH 9.5 & dKH 15. Not many fish do
well without some work on my water. And the RO water, well water and
acid mix I was using suddenly became very cloudy with precipitate.
After this I started having the fry problems. With all the trace
elements in the HBH balance blocks, I've no clue as to what it added
that was missing from the water, but it sure did solve the problem.
I do know adding 1 block (about 3/4 dissolved) to a 10 gallon tank
filled with only RO water yielded these test results GH 140 ppm, pH
7.0 and dKH less than 1. This was using the Tetra test kits.
I've also noticed an increase in the color of two different strains of
werneri since adding these blocks to their tanks.

Cary Hostrawser

Minnesota Aquarium Society

Rainbowfish Study Group of North America