If you have a tank and want to avoid dosing with copper here’s what I would recommend to try and keep your tank ich free.
1 - Quarantine all your new fish separately for at least 2 weeks before adding them into your main tank. Treat as necessary with either Ich-X or Formalin.
2 – Invest in a UV sterilizer for your tank. This way it will kill off any ich present in the tank and stop it from spreading, thought this does not get rid of it entirely, just manages the population in your tank.
3 - Keep a few natural pest eradicators in your reef tank, such as cleaner shrimp or cleaner gobies like the Neon goby. They will naturally eat the parasite off of other fish, although this method has mixed results.
If you have any other tips or tricks on keeping ich out of your tank or treating without copper please share!
Just to point out - Ich-X is formalin and malachite green. You do not want to dose that with formalin, and Ich-X is really only effective for some freshwater fish (and then, the malachite green can cause toxicity in scaleless fishes). Formalin at 25 ppm is effective against some protozoans, but marine ich is often able to keep reproducing.
Formalin has human health issues and I really cannot recommend it for use in people's homes. I've been exposed for decades and I'm still above ground, so a single exposure in a home probably isn't going to be too much of a concern, but keep it out of reach of children!
UV sterilizers do not control flukes, and there is ample evidence that hobby sized units cannot control active infections of marine ich:
UV sterilizers
Ultraviolet (UV) sterilizers are also sold as a “cure” for
Cryptocaryon. The problem is that most hobbyist-sized UV sterilizers do not have the power to make an effective kill on the relatively large
Cryptocaryon parasite. Additionally, UV sterilizers are effective only on the tomite/theront stage, as this is the only point where the parasite is even present in the water column.
For velvet,
Amyloodinium, the fallacy here is that tomites/theronts
must leave the fish. Actually, some of them may get caught up in the fish’s mucus and stay attached until they become infective trophonts again. For
Cryptocaryon, the tomites/theronts do seem to need to leave the fish, but with side stream application of UV (where only a portion of water passes through the unit) DWELL TIME becomes the limiting factor. Only a portion of the theronts are killed before enough of them attach to the fish to continue the infection. This means that UV sterilization will not eliminate active
Cryptocaryon infections from a single aquarium. Where it does have benefit is in eliminating tomites as they pass through a filtration system from one discrete tank to another (like in a public aquarium or fisheries lab). Decades ago, diatom filters were touted as cures for ich and velvet. The same issue applies with them; there are adherent forms of these protozoans that can continue to infect the fish without ever having to leave the fish’s body. Even if they do, the same “dwell time” factor means that some theronts will still be present in the water column to infect the fish.
A recent study (Ge-Ling, 2022) indicates that the UV dose required to kill
Cryptocaryon theronts/tomites is 185,000 uw/S/cm2. They do go on however, to conclude: “ …both ozone and UV are ineffective in controlling infection within an individual aquarium because of the adhesive nature of
C. irritans tomonts (Ma et al., 2017). Therefore, the focus on UV and ozone treatment should prevent live theronts flow into aquaculture ponds. Second, the tomonts are strongly resistant to UV or ozone than theronts, implying that recommended production doses cannot wholly kill tomonts….”
