Re: [Killietalk] RO advice now viabilty of eggs in hard water

[Gary Elson or Mary Frauley <fraulels at videotron_ca>]

I think David's point is an excellent one. I'm also a believer that what we 
learn in one group of fish can be relevant to another - in this case, 
Apistogramma dwarf cichlids and killies. It would seem to me, in my 
untrained analysis, that blackwater, extremely mineral poor niches are a 
blessing and a curse. Small fish can flourish in them in the absence of 
other species that can't adapt to the extreme. But if the species becomes 
overly specialized and the environment changes, that's it folks. Their only 
hope is the fundamental messiness of nature.

I also assume that fish move into extreme niches, from less extreme ones. 
The move may be ancient in human terms, but it happened.

I've been able to breed a lot of blackwater Apistogramma (and West African 
Nanochromis) in water they should not be able to breed in. In harder water, 
a lot of eggs do not hatch. A species that might give you a consistent 100 
fry in soft water may give you 10 young in technically inappropriate water. 
You can breed them in what is "tap" where I live, but you won't breed many. 
This is something I've thought about facing high rates of egg death in 
killies, when I've brought in a new species and tried them in tap, and had 
maybe one egg in five or ten hatch. I soften the water and the hatch rate 
often goes up. My assumption is that not all eggs are identical, and that an 
egg that may be a "defective" throwback in a Brazilian stream is perfect in 
the 15 gallon downstairs over by the lampeyes.

Wright's observation that not all water coming from the tap is the same is 
interesting. If I can breed a killie, dwarf cichlid or tetra in rainwater, 
it won't have water treatment chemicals in it, so  that could be a factor. 
But I've never seen a pattern in rainwater versus R.O. affecting eggs.

One of my favourite Apistogramma is gibbiceps. One form comes in from 
non-blackwater, and is able to breed like rats in my tap. Another identical 
looking gibbiceps from a blackwater region needs very soft water for the 
eggs to develop. It's fascinating, and again, potentially killie-related. 
Nature is not a rule-bound system.

And, yeah, I know - tap water is not natural...

As hobbyists, we rely on observation, and what we can see is obviously not 
all we'd like to know. Still, it's what we "work" with, and my experience 
with Apisto, killie and Characin breeding says water hardness is an 
important factor for breeding rainforest fishes. However, I don't even 
bother measuring pH anymore. I think we just need to keep experimenting, 
keep noting (AND SHARING) our results and our attempts, and keep avoiding 
over-generalizations.

Gary 


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