Re: [RML] Question about Artemia and frys

Scott Davis (unclescott at prodigy.net)
Thu, 3 Mar 2005 07:04:32 -0800 (PST)

I apologise for the last mess. Not through the first
cup of coffee.

This is probably old news to you Magnar, but perhaps
of benefit for lurkers. If you are feeding brine
shrimp and the fry are not able to eat all of them, it
is to your advantage (once the rainbowfish eggs have
hatched) to introduce several small pond snails to the
tank and to even more militantly siphon uneaten food.
Rotting brine shrimp seems to provide an excellent
environment for a bloom of velvet (Oodinium, more
recently Piscinoodinium). It is frustrating to have
your fry growing and thriving, only to see their tails
clamp and then have them rapidly die or disappear. I
fear that velvet is responsible for a number of
"mystery deaths," unexplanable because the afflicted
fry are so small and they perish so quickly, that
observers don't get a chance to understand what is
happening.

When some featherfin youngsters came down with velvet,
I was pleased that partial water changes, salting the
water, treating with acriflavin and darkening the
tank, allowed about half of the fry to return to
robust health. And that was in a greenwater tank with
snails!

Naturally I would have preferred to avoid the crisis
altogether. Brine shrimp, and foods with shrimp as an
ingredient, play an important part in the raising of
fry. But uneaten shrimp, not cleaned up quickly (one
way or another), can open the door for outbreaks of
velvet, especially with rainbowfish, Anabandids,
killifish and even some catfish such as the Ancistris
(on the gills).

All the best!
Scott