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Re: mineral requirements
>Date: Tue, 4 Nov 1997 10:55:15 -0500
>From: sueandlee at webtv_net
>Subject: Re: KillieTalk Digest V1 #19
>
>Good morning ,
>
>Just wanted to throw this out for comment. What about paste foods ? What
>about minerals .
>
>I feel that enriching the BBS is a good idea ,healthy food makes better
>killies .
>The drawback is it has some very hard limits , like what and how much
>are the BBS actualy a vehical for .
Enriched BBS are a vehicle for essential fatty acids. "Sanders Docosa Gold"
refered to by Lee Harper refers to docosahexanoic acid -- the most
important essential fatty acid. What ever amount gets into the shrimp and
is eaten by your fish is more docosahexanoic acid than BBS w/o
supplementation will have (near 0).
>
>Paste food (to me) is a much better way of getting specialized
>nutritional elements into the fish . Using agar as a binder has a
>plus,since it is made from a seaweed it provides trace minerals .Mineral
>suplements seem to be one of the most over looked / under rated items in
>killie nutrition .
Agar-based paste foods are great, but not because of their mineral content
(see below). My advisor for my masters degree made an excellent food for
his experimental striped bass from a mixture of pig gelatin, ground salmon
chow and ground squid. When cooled in a tray it had the consistency of
very thick fudge and it produced the healthiest captive striped bass I have
seen without additional dietary supplements.
The addition of zeolite (the ammonia remover) or
>latralite (?spelling) have remarkable effects on growth , health .
The above 2 compounds are ion exchange resins. They can improve water
quality in your tanks (by chelating ammonia and/or other compounds) but
don't really provide any essential minerals that are not already in your
water.
Also
>, at the time I was playing around with trying to find a cure for the
>skewed sex ratio of Rivulus Xiphidius .
>Of all the wacky things I did ,The addition of minerals seemed to
>increase fertility or maybe more correctly , made a healthier egg .
It has been known for some time that the calcium content of the water can
have an effect on fertilization rates of fish eggs. In many fish species
from soft water environments (where Calcium content is low) sperm will not
successfully fertilize an egg if the calcium concentration is too high.
This is one reason that many killie keepers with hard alkaline water
(liquid rock) have a hard time successfully breeding rainforest killies w/o
an RO system. The kicker is that calcium is involved in the fertilization
process so having NO calcium in the water is not good either.
>
>Respectfuly ,
>
>Lee Palmer
>
According to Hepher (Principles of fish nutrition. In: Fish culture in warm
water systems: problems and trends. Shilo, M. and Sarig, S. Ed., 1989, CRC
press.) mineral suppplements for fish are generally not necessary. This is
due to the fact that unlike terrestrial animals fish can absorb many
minerals, such as Calcium, from their environment. Other essential
minerals are found in most natural food items at concentrations exceeding
the needs of the fish. Thus if you feed some live foods to fish mineral
deficiencies should not be a problem.
Vitamins, on the other hand, may potentially be deficient, but only if a
fish is fed an unsuitable diet (ie: carnviorous fish fed primarily plant
products). Carnivorous fish, such as most killies, fed a diet of live
foods or flake food should not be deficient in any vitamins. The exception
may be omnivorous killies, such as some of the pupfish, can be deficient in
some of the B-complex vitamins that are most plentiful in plant-based
foods. On the other hand, intestinal bacterial flora of warm water fishes
have been shown to produce vitamins themselves. Some of these are absorbed
by the host fish therby aleviating the need for dietary supplementation.
The bottom line is that if you feed your killies a diet that is largely
representative of what it would eat in the wild (include some live foods
for carnivores and some algal foods for omnivores) vitamin and mineral
deficiencies will not be a problem. In general, only fish fed soley on
artificial diets have showm symptoms of vitamin or mineral deficiency and
the newer flake foods have sufficient vitamin additives to prevent such
problems now. Unless the species of fish you are keeping has a
particularly specialized diet (like some of the catfishes) vitamin and
mineral deficiencies are largely a red herring in regard to fish health.
Regards,
Eric Lund
lund at umbi_umd.edu