Advice from a vet - You may find this interesting...?

[eastofthesun46]

Following extensive troubles with my filter, my clown loach Eric has suddenly lost weight. Not very much, but enough to cause concern.
I got onto my vet, hoping to get hold of some levasole for the tank. Instead, I got a referral to another vet, who treats fish (this is a rarity in England!). After a few phone calls, I managed to get hold of the man in question, who told me a number of interesting things...

Apparently, it is more important to reduce your nitrite levels than your ammonia - nitrate acts like carbon monoxide when it comes into contact with a fish's haemoglobin, bonding permanently and slowing suffocating the fish. Ammonia is still highly toxic, but it needs a higher concentration over a longer period to kill.

He also said that he has never come across a single case of worms in his career. When I asked him if there was any point in me treating with levasole, however, he could not have been more positive!! Apparently the immune boost that levasole provides allows the fish to fight off their ailments themselves, which is much better for them than dosing the tank with random treatments. It struck me that this might explain the lower success rate for treating skinny with fenbendazole and other de-wormers in comparison?

Apparently, though, he was by law not allowed to prescribe levasole. For some reason, in the UK only farm supply stockists can provide levasole treatments. He suggested that I hit a couple of farm shops masquerading as a sheep owner, and try to score some drugs! (I decided to cop out, and ordered Jungles Anti-Parasite Med Food online instead).

He suggested that I begin treating for an internal bacterial infection, and alternate with levasole if I can get hold of it - so the same answer as LOL, if only for different reasons!

But one warning he did give me was that it's very common for young fish to die. Apparently this has a massive evolutionary benefit to the species (the younger, weaker ones get picked off by predators instead of the rest), and that some species even seem to have designated dudsto protect the rest of the group. Not exactly what I wanted to hear, but oh well! I hope you found this as interesting as me!

[Donna]

Too bad you're not in the US, where we can legally buy all the levasole we want (or can afford). It's given to rehab opossums as a wormer, or half-strength purely for the immune system boost.

[Diana]

Great that you found a vet that actually treats fish!
Yes, he is right that nitrite (with an I, not an A) (NO2) causes a problem like carbon monoxide in the blood. To find out more about it google Brown Blood Disease.

As for what is a 'safe' level of either ammonia or nitrite, it depends on so many things that there is no one number that is OK.
Fry of most species are more delicate, and require less of either toxin to cause problems.
Some fish species are more tolerant of low levels of either or both.
Water chemistry affects the toxicity: Ammonia in a low pH tank is more in the form of Ammonium, NH4+ and is not so toxic. In water with an alkaline pH more of the ammonia is in the form of NH3, and is toxic.

The 'safe' numbers have not so much been studied, as just figured out as generally OK under a wide range of conditions.
Since other things besides pH can affect ammonia, keep it under .25 ppm (mg/l). If you know the tank is definitely acidic, then you might be OK to allow it to get a bit higher, but then you must not allow the water to become alkaline.
Nitrite of up to 1 ppm can be tolerated. Add sodium chloride to the tank at the rate of 1 teaspoon per 20 gallons. This is a very generous dose as far as Brown Blood Disease goes, so it does not matter if you are using American gallons or Imperial. The chloride from the salt interferes with the way the nitrite crosses the gills and provides some protection.

http://edis.ifas.ufl.edu/pdffiles/FA/FA04100.pdf

[fhm_usa]

Too bad you're not in the US, where we can legally buy all the levasole we want (or can afford). It's given to rehab opossums as a wormer, or half-strength purely for the immune system boost.

The only sad thing is it's currently out of stock when I tried to order it they said it's been back ordered for almost one year already

[eastofthesun46]

Yeah, I tried ordering some from a few pharmaceutical companies, but to no avail.
The jungle fish food has turned out pretty good - I bought the tropical fish version, rather than the pond, but I am finding even this is too big for my tiny fish!! Ground up, it is pretty popular with the fish though!