Re: [Killietalk] Flow-thru/Rec. Systems with Various sp. of Killifish

[LeeH920226 at aol_com]

In a message dated 11/22/03 2:48:21 PM, bjc3 at centurytel_net writes:

<< However, in ponds, such as 
Nothos live in, that probably is insignificant. I would assume that the 
flora in the water and substrate break down these organic compounds quite 
readily. I don't think we can come close to mimicking the flora of a 
natural environment in our tanks. >>

I have no direct information on Nothobranchius pools, but South American 
annual pools are flooded by rain water and ground water levels which flush out the 
water and the volume per fish is much higher than we maintain in our tanks. I 
assume that in most cases the water is continually being diluted with new 
water from the rains and ground water until the wet season is ending. At this 
point the fish are old and dying of many causes including predation and aging, so 
water quality may not be a factor. I assumed that the fish that would really 
thrive on a continual replacement are the stream fishes, like Rivulus and 
Aphyosemions, but my South American annuals also seem to benefit. 
    I especially noticed the growth rate of some Austrolebias bellottii 
young, which I raised side by side with normal manual replacements on a weekly 
basis and the flow through system. The growth rate in the flow through system was 
at least twice that of the manual method. However, the method of pairing fry 
to improve the sex ratio may not work in a flow through system. No data yet on 
this from me but I would guess that Jim Robinson has the answer to that 
question.

Lee Harper
Media, PA

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