Copper in Reef Tanks & What it does to Coral

Many of us in the reef hobby are familiar with the element copper. Atomic number 29 is a recognized orange metal in its purest form. Though I doubt you’ll see it that way in your reef tank. People may use it as a therapy for ich or another sickness in their fis. Although copper compounds are considerably more common in aquariums. Those compounds are frequently invisible in solution; a small amount of copper has a significant influence. But a higher concentration will give it a lovely blue greenish color.

What is a safe copper level, effect in a reef tank?

So, what is a safe copper level? Unless you’re testing your tank with a Triton kit or any ICP-style test. There is no such thing as a safe level of copper. Most home test kits will only test in parts per million. Possibly even parts per billion, and even one part per million is far too much for most coral. If not all coral. However, if you use an ICP test kit, you might get one or two parts per billion. Which you should be cautious of, but even those tests should not identify any copper.

So, if you find any copper, it’s most likely producing problems, and these problems tend to worsen over time.

Copper should never added to a reef tank on purpose. If you need to use it to medicate a fish, for example, to get rid of ich or something similar. You must do so in a separate tank. But that’s a topic for another essay; for now, suffice it to state that you should never add copper, or anything containing copper, to your reef tank.

Even in the absence of coral, copper can slowly leach out of living rock or anything porous over time. So live rock or anything porous from a copper-containing tank should never put in another coral-containing tank. This isn’t to claim that coral doesn’t require any copper.

In fact, even for their normal biological activities, all living creatures require trace amounts of copper. Copper, for example, required for the formation of the elastin protein. That’s the substance that allows you to open your fingers by stretching your skin and other tissues. Elastin found in coral and Cnidarians. They also include collagen, which is a vital protein in your body. This level of copper will be almost imperceptible in our tanks. And it will delivered by the fish and coral food you’ll add. Or perhaps in your water changes, because your tap water, even good ROID water. Will very certainly include microscopic bits of contamination.

So, if you do add copper to coral, what effect does it have? In a nutshell, it kills it. But how do you do it? To find an explanation, I went to a library and found a study titled “Sub-cellular injury by copper in the cnidarian Zoanthus robustus” from 2010.

It’s really cool, and I’d recommend it. Zoanthids chosen as the subject of study since they are essentially a larger version of the normal coral polyp. Overall, Zoanthids have the same morphology as the tiny polyps on your Acropora. But because they’re considerably larger, you can see the changes and damage much more easily.

Excess copper in the water can be harmful because it aids in the creation of hydroxyl radicals. Which can harm a variety of organisms within the coral. Now, cral can get rid of those free radicals to some extent, but they can only do so much.

Copper exceeds that capability, causing damage to amino acids and even DNA itself. Copper can actually block the sites that coral uses to export those molecules. So even if coral can tie up those free radicals, it can’t remove them from its tissue. After just 14 days of exposure to 50 parts per billion copper, a study of Pocillopora coral find that polyps retracted and tissue is lost. Another coral in a different study has exposed to copper for 15 days before scrubbed with a toothbrush. The corals that exposed to copper died, but the corals that not exposed to copper recovered.

So they detected oxidative damage in the tissue that really removed in that test. The free hydroxyl ions that we were talking about were causing damage at a subcellular level that was unseen.

In comparison to the control polyps, the research Zoanthids constricted and noticeably less flexible and tougher to cut after exposed to 20, 40, 60, or 110 micrograms per liter of copper. Which is virtually directly convertible into parts per billion. Their bases, where they grip the rock, also covered in algae that wouldn’t ordinarily seen there. The copper penetrated a barrier or membrane within the polyp that would typically prevent the algae from reaching the polyp’s base. When they examined the Zoanthids under a microscope, they discovered that the polyp walls substantially thicker after exposed to even 20 parts per billion copper for nine to eleven days.

The copper made the Zoanthids create a lot more collagen, which thickened and made the walls less flexible.

The thickening also restricted the amount of interior space available to the coral for feeding, water flow, and other essential functions. Coral isn’t the only sea creature that develops collagen problems after being exposed to copper. Sponges have also been discovered to do the same function. When a sponge was placed in polluted silt in the ocean and allowed to grow over time. The sponge’s tissues thickened, allowing less water to pass through them.

Of course, sponges rely on filtering water and transporting it through their tissues, so this is bad news for them. In reality, something similar could happen to you. No, not water difficulties or anything like that; it’s chewing on Areca nuts, also known as Betel nuts, that causes your mouth’s tissues to produce more collagen.

It can develop so bad that you won’t be able to open your mouth at all since you can’t stretch your lips any longer. Oral submucous fibrosis is a condition that can progress to mouth cancer.

There are a few different ways to test for copper. The one you use depends on the type of copper compound you’re looking for.

At the very low end, an ICP test is going to be the most accurate. So an ICP test is probably your best choice for consistently detecting extremely low levels of copper. The test kits to use if you’re dosing Cuprion or Cupramine are either the Seachem or the Salifert test kits. If you’re using Coppersafe or Copper Power, you’ll need to use the API test kits instead. Those products employ different copper compounds. Copper is a fascinating element to have in a reef aquarium.

It’s vital for life, but at just a slightly greater concentration, it causes all those free radicals and collagen overproduction. Toughening the coral’s tissue and obstructing the regular living processes that our coral needs to survive.

These effects are additive, and it’s unclear if they will return to normal after the copper is removed. Some of the alterations, such as DNA damage, may be permanent. Which is just more reason to keep copper away from your coral. Even if a level of copper isn’t obviously lethal and doesn’t kill your coral right away, it still causes damage.