I never had Velvet. I had White Spot and I used a medicine called "QuICK
Cure" to treat it, along with gradually raising the temperature to about
85F, but I had no live plants at the time and I think that medicine is bad
for plants. Having plants changes everything. Some use salt but that's also
bad for plants. In the case of plants I'm not sure what I would do. I'd be
tempted to remove the fish to another temporary hospital tank and treat them
there, and let enough time pass for the parasites to die off (lacking any
host) in the main tank (raise the temp as much as the plants will stand to
speed the process) and then put the fish back afterward. I don't know how
practical that would be, and I don't recall ever hearing of anyone doing it
that way (that I can remember) but it's what first comes to my mind at
present. I tend to do whatever seems logical when the need arises, and
knowing that the parasites will die off without a host, that would be my
thinking in such a case. I see in a later posting that 'Reel McKoi' wrote:
"I think what you call "red blotch" is what we call "contagious ulcers" a
condition caused by bacteria that is almost impossible to treat." - I would
fully agree with that assessment, and it sounds exactly like what I have
experienced in the past.
Healthy fish are to some degree resistant to White Spot (and I would
assume to Velvet also), but it is a known fact that adding cold water to a
tank can allow the parasites to gain advantage over the fishes resistance
whereas the fish might have been able to resist being infested otherwise. I
would never do it. More frequent water changes are needed in an overstocked
tank, and not cleaning the gravel and other parts of the environment will
lead to a dirty environment that harmful bacteria will thrive in. All of
these factors combine to lower the fishes resistance to disease, and since
bacteria are always present, the only defense the fish have is a strong
immune system and robust health. A clean tank and stable environment are
essential for healthy fish. Think of how in the wild they have a large body
of constantly circulating clean pristine water (with plenty of sunlight
which kills bacteria) with a low level of bacterial concentrations, and
plenty of dissolved oxygen; that is what you want to try to replicate in
your tanks. Thinking of sunlight killing bacteria, a U.V. sterilizer unit
would probably help a lot. I've never had one but it's been on my mind some
and it will kill both parasites and bacteria. The nitrifying bacteria are
mostly on surfaces and not in the water, so it won't affect them much. I
suspect that using a U.V. unit prevents a lot of problems and would provide
some peace of mind.

Fedor


wrote in message
ups.com...
Fedor,


Thanks for your replies - it is good to have someone elses thoughts
when you are unsure what is right or wrong.
i have posted this on yahoo groups but everyone there only seems
interested in arguing!

I am begining to form an idea of how it may all have gone wrong

The tank was overstocked, i never cleaned all the gravel, and i
regularly added cold water to get the catfish to spawn.
These things together would have had an effect on the fish even though
they all looked great, then i added some plants, some of which i know
were from a regular customer at the LFS who has a CO2 setup at home,
he brings in plants when he has too many and the guy at the fish shop
sells them (actually he gave me a load to keep me sweet because i
supply him with catfish) anyway, i think i remember him saying that
the guy had just brought the plants in recently - this would mean that
parasites may have still been ailve on them or in their water.

I think that the corydoras died of an infection called red pest,
possibly brought on the the attack of parasites, the others developed
parasite infestations later and their bacterial infections were as a
result of this.

The thing is now i need to get rid of the parasites which i believe to
be velvet and white spot at the same time. Do you know of a treatment
for both together?
I have read about copper which is used for ridding a tank of snails,
but i dont like the idea of it, it is a poison. And it would damage my
plants.
There is also methylene blue but it will have side effects too and i
don't know how effective it is.
Like you i subscribe to the idea of minimal intervention, letting
nature (such as it is in a fish tank!) look after itself, so i may
just keep on removing sick fishes, changing the water, cleaning the
gravel etc etc and hoping the fishes iminutiy in the main tank takes
care of it


If anyone does know a way of dealing with white spot and velvet at the
same time please share it with me


Thanks


chris