Backyard Aquaponics
A place to discuss aquaponics

OzY, you mention 30C for an "extended period of time". Any idea on how long it would take to clean the system without adding salt?

G'Day HD, to combat ich you need to understand that its lifecycle can be divided into three (some say four) definate steps and they are more vulnerable during some of these steps than during others.

Step 1: Trophont. The prefix 'troph' means feeding. Ich ONLY feeds during this stage. If lands on the fish and begins to form the cyst we see and is impervious to medication during this stage. This stage can last several days at lower temperatures but is greatly reduced at higher temps. So the first thing higher temps does is reduce the length of the invulnerable stage.

Step 2: Tomont: The cyst bursts and the ich parasite (called a tomont at this stage) makes its way to the substrate where it attaches to something solid and proceeds to divide making up to 2000 new ich parasites per tomont. During this stage they can be stressed and killed by temps around 30 degrees Celcius. But the main thing it does is speed up metabolism of the ich so that it uses its reserves up quickly and releases the next stage which must find a host (your fish) again very quickly because this stage does not eat. They swim for a few hours and then settle on the bottom. At high temperatures this stage lasts only hours where as in a cold water pond it may last several days.

Step 3: Tomites: When mature the tomont releases the tomites which must swim to find a new host (your fish). At high temps. it has only hours to do this because the high temp speeds it's metabolism and the swimming uses significant amounts of energy. Many will die before finding the host. Some will find the host and repeat the life cycle but their numbers will be seriously knocked about. If you leave the temp. high the next lifecycle, with drastically reduced numbers, will also be accelarated and decimated. And so it goes... You can see that each lifecycle is being disrupted by the high temps and after a week of temps of 30 degrees (oscars can handle that easily) many lifecycles will have been and gone and the attrition rate in this time will be significant enough to render the parasite beaten. You can then keep the parasite at sub-clinical levels by lowering your temp. by a few degrees to about 27 degrees celcius, which is good basic temp. for oscars anyway, and it is unlikely you will ever have trouble with ich on your oscars again.

I have used malachite green (in the dark) before but this is copper based and copper is suspected of contributing to lateral line degeneration (AKA hole in the head syndrome) in oscars so now prefer to ONLY use a week of 30 reduce to a maintenance temp of 27(ish). You may not erradicate ich all together this way and sudden drops in temp can cause a new outbreak but the chances are given sufficient time you will erradicate it altogether.

So how is the system doing?

I am moving into stage 1 of my attempt
April 14-30 Cleaning the 100 gallon tank, filling it and checking that everything is in working order for the next week or so.
April 30-May? put in 20 feeder goldfish and start the cycle
mid to late May add another 50 feeders
early June to mid June add the last batch of feeders (20-30)
End of June early July move in 6-10 3" oscars (probably fire tigers)
Grow and breed oscars (crosses fingers)

Anyway thats the plan
It'll probably go more like fill tank install feeders pump dies
buy new pump restart the system install fish the tank leaks
fix leak refill tank install feeders mystery desease duh-ohh
Ah well such is the sport