If you keep fish long enough, you will get sick fish. The most common diseases fish get are external parasites such as freshwater and saltwater ich, marine and freshwater velvet, anchor worms, and brooknella. All of these diseases can be easily treated with one simple medication, Copper. Copper has been around for a very long time and the Copper Power brand has stood out as the go-to copper medication in the aquarium industry for many years. If you have never used copper, here is a brief guide on how to use the medication. Understanding how to use copper is essential to any meaningful quarantine of marine fish.

Cautions
While copper is a very gentle medication that does not disturb the biofilter like many other medications, there are some cautions. Copper will kill any invertebrate. All snails, crustaceans, worms, and corals will not survive a copper treatment. This is why copper is so effective at eliminating invertebrate parasites, but it is also why you can not use copper if you have any of these animals.

In addition to killing all invertebrates, some fish do not tolerate copper. All sharks, dragnets, and rays should never be treated with copper. In freshwater tanks, scaleless fish such as loaches should not be treated with copper.

Pick the right formula
There is a standard Copper Power Marine for saltwater fish and a Copper Power Green for freshwater fish. Both will work in fresh or salt water but it seems that fish tolerate the correct formula better so it is best to stick to the correct formula for your given application.

Start by adding copper
Before adding copper, remove any chemical filtration media that could absorb the medication. Copper Power has a recommended dose of 1 oz per 20 gallons of system volume. We recommend you add this over two days for a gentle transition for your fish. In our experience, this dosing recommendation is a bit conservative. The manufacturer also states that a copper level of 2.5 ppm is recommended for treatment. If you don’t achieve this copper level then you might weaken diseases allowing fish to recover, but you won’t be effective at truly eliminating diseases.

The best practice is to start with the recommended dose and then use a copper test kit to confirm the copper levels in the aquarium. Our favorite is the Hanna High Range Copper Colorimeter Checker. It is accurate and simple with only one reagent. Results show up in less than a minute. If you are looking for a budget option, then you can purchase a Seachem MultiTest Copper Test Kit. Once you know the copper levels you can either add some more Copper Power or do a slight water change to dilute the treatment. Given that the recommended dose is conservative you will usually need to add a bit more copper.

Wait
Once you have reached the correct level of copper you do not need to add any more unless you remove some of the medication with a water change. After about a week, most disease symptoms will be gone from the fish. Because some parasites can lie dormant in the substrate or rockwork of the aquarium, it is best to treat with copper for a full 30 days so that all dormant parasites will emerge and be killed by the medication. Doing this will make sure all the disease has been removed from the aquarium.

Wrapping it up
That’s all there is to copper. Simply add the treatment at the right level and wait a month, and a whole host of diseases will be eliminated from your aquarium system. Copper power is extremely affordable and effective at eliminating fish disease.