Re: NANFA-- white spots on Fundulus cingulatus
Tue, 5 Aug 2003 11:51:12 EDT

I don't know if this has anything to do with your fishes' white spots, but I
collect speckled dace from the local waters from time to time here in Idaho -
most often in the winter for the purpose of being feeder fish for some of my
other fish. Several years ago I noticed that whenever I had the dace in an
aquarium with other fish and some stress factor ocurred, such as electricity goes
of for awhile, the temps get too warm, too many fish, etc. and some of the
dace would break out in white spots. Although the dace seemed to survive the
spots for a prolonged period of time, other fish contracted the spots a few fish
at a time and were usually dead within a week. It's happened enough times
for me to suspect the dace as carriers - not necessarily immune to the disease,
either as they usually die as well - they just seem to last longer than the
other fish and they seem to always be the first fish to break out with the

If my observations are somewhat on target, I'm thinking the two biggest
stressors are overcrowding and water temps. If you're having this problem in the
summer, my first guess would be too warm of water for cool water species and
too cool of water for warm water species. I've noticed that mollies do not
tolerate cool water very well nor do my dace tolerate warm water very well.
Unfortunately, I don't have successful experiences at reversing the white spots -
once my fish get them, it's usually only a matter of time before they die.
Now, I'll sometimes have a few fish within a group that don't get the spots and
once the crowding/temperatures are corrected, those remaining fish seem to
survive o.k. until there's another stressor and then the white spot infection
starts its cycle all over. I'd say avoid overcrowding or keeping fish in waters
that remain at temperatures at the edge of or beyond their comfort range and
you may not get it in any of your other fish, but as for how to treat fish
already infected, I can't say. Once my fish have become infected, it has just
been a matter of time until they die with the exception of some sunfish that
survived after receiving a salt and/or salt water bath.

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