How to kill Ich Parasites and marine velvet in saltwater aquarium

How to kill Ich Parasites and marine velvet in saltwater aquarium is a controversial subject in the saltwater aquarium hobby.

How to kill Ich Parasites and marine velvet in saltwater aquarium is a controversial subject in the saltwater aquarium hobby.

Many reef stores and saltwater aquarium hobbyists will say once you have ich parasites in your tank, you will always have ich in your tank.


Ich will never be present in your saltwater aquarium if you never allow it in your saltwater aquarium.

Are your saltwater fish dying for no reason? Gasping for air and not eating? Not moving? Hiding? You may have Ich parasites or Marine Velvet in your saltwater aquarium.

Ich is a parasite and needs to be killed. In this post I will explain how to kill ich in your saltwater aquarium and how you can prevent ich from entering your saltwater aquarium forever.

What is Ich in a saltwater aquarium?

This ich parasite is a nasty silent killer. Ich parasites embed themselves in the flesh of fish and eat away at your fish.

Maybe you noticed your saltwater fish swiping quickly against rocks or sand in your saltwater tank. This is one of the signs you may have ich parasites in your saltwater aquarium.

Saltwater fish that have ich parasites under their flesh attempt to relieve the itching and biting by the ich parasite by scraping itself along the rocks or sand in your saltwater aquarium.

It’s important to note that if you have one saltwater fish in your aquarium with ich, they will all get it. Ich parasites live in the water column and it’s only a matter of short time until all your fish are infected.

The Ich Parasite in your saltwater aquarium

After a few days of feeding on your saltwater fish, the ich parasites drop off in the sand bed and encrust in a hardened shell.

Over the course of 28 days, the ich parasites multiply, releasing hundreds more ich parasites into your tank, that seek out a fish to host and eat from the inside out.

After a few more days, these ich parasites drop off the fish and encrust again for 28 days. In a short amount of time, the amount of ich parasites in your saltwater aquarium will number in the thousands.

Signs of Ich on saltwater fish

There are signs to lookout for to see if your fish have ich as you monitor your saltwater fish daily

  • Saltwater fish swiping along the sand or rock in your saltwater aquarium
  • Saltwater fish not eating as much
  • Saltwater fish swimming in a jerky motion as they swipe along the sand floor
  • Small white specs on the body of saltwater fish that resemble tiny pimples or salt
  • Coloration of saltwater fish isn’t as vivid or colorful
how to kill saltwater ich on fish in your saltwater aquarium. saltwater ich on fish looks like salt.
saltwater ich specs on fish look like salt

If left untreated, your saltwater fish will die and you will always have ich parasites in your saltwater aquarium.

Myths On How To Kill Ich in a saltwater aquarium

  • Soak saltwater fish food in garlic
  • Garlic raises saltwater fish immunity to battle ich parasites
  • Lower salinity in saltwater aquarium (lower salt level)
  • Overfeed your fish so they get super healthy
  • Drop vitamin supplement in your saltwater aquarium for the fish

The myths on how to kill ich parasites in a saltwater aquarium go on and on and none of them work.

Saltwater Aquarium ich parasite FACTS and MYTHS

There is only one way to kill ich parasites and get them out of your saltwater aquarium forever!

The process to kill ich will require some patience but once you rid ich from your saltwater aquarium, both you and your saltwater fish will be very happy.

How to get rid of ich parasites in your saltwater aquarium (the only way)

In order to kill ich parasites in your saltwater aquarium, you must starve the ich parasites. How do you starve the parasites? Remove their food source from the saltwater aquarium; your saltwater fish.

You MUST QUARANTINE, QT, your saltwater fish in another tank.

With no fish to feed on, the parasites will die in your main display tank. Your main saltwater tank that is infected with thousands of ich parasites much be kept fishless for 6 weeks minimum! Some saltwater aquarium hobbyists choose to go 8 weeks just to make sure.

The reason for 6 weeks is you must break the ich parasite life cycle.

Removing saltwater fish from your aquarium for a week or two will not affect the ich parasites that are encrusted in their hardened shells waiting to hatch (28 days.)

How to Kill Ich Parasites in your Saltwater Aquarium FOREVER

To make sure you kill all ich parasites, you must wait 6 weeks minimum.

After 28 days of hatching, if new ich parasites do not find food (your saltwater fish), they will die within a few days to a week at most.

You do not need to remove coral or inverts from your main saltwater aquarium. You are only removing the ich parasites’ food source; your saltwater fish.

This is how I KILLED the ich parasites in my saltwater aquarium for good! I learned the hard way by losing most of my fish when I was starting out in the saltwater aquarium hobby.

How to kill ich and marine velvet in saltwater tank – the only way to kill ich

Feeding your saltwater fish well and making sure they are healthy in your aquarium is not enough.

Saltwater ich and marine velvet and oodinium is a parasite not a disease. These parasites must be removed permanently from your saltwater aquarium by letting them die by starvation: removing its food source; your fish.

Click here for my book on Amazon that walks you through the entire process if you need more info on how to kill ich in your saltwater aquarium.

I wanted to share what I have learned about ich and marine velvet to help your saltwater fish and aquarium stay healthy.

Every time you buy a new saltwater fish, you MUST keep it in the separate quarantine tank for 6 weeks before adding them to your main saltwater tank. You don’t want to infect your other saltwater fish in your healthy aquarium with a new fish carrying parasites!

Important – Saltwater fish at the local reef store are in separate aquariums but all those aquariums use the same large filtration system in the back of the store. If one fish has ich in its tank, it will spread to all other tanks. This is the reason you MUST quarantine all new saltwater fish before adding them to your main saltwater aquarium.

How to treat saltwater fish for Ich

Once you have captured all your fish (you may have to remove many rocks from your saltwater tank to catch ALL THE FISH) you will place them in the 2nd aquarium you setup.

Make sure the 2nd saltwater aquarium (Quarantine Tank, or, QT) is large enough to accommodate all fish; they will be in there for 6 weeks.

The QT must be cycled or your fish will die. Read my post on how to cycle a saltwater aquarium; this is VERY IMPORTANT!

Cycling a saltwater aquarium means having the right amount of good bacteria in a saltwater aquarium or your fish will die of ammonia poisoning. Ammonia will kill your fish very fast. Ammonia is fish pee and uneaten food and waste.

If you need to cycle your saltwater aquarium quarantine tank in a hurry, you can place a rock or sump sock or anything that was in your main saltwater aquarium. This will have bacteria on it, which will battle the ammonia.

simple saltwater quarantine tank setup to kill ich in saltwater aquarium and saltwater fish.
Simple saltwater quarantine tank setup

Yes, I know it’s an extra expense and hassle to setup a QT for your saltwater fish but you must do this to kill the ich in your saltwater aquarium and save your fish.

Make sure you take care of your saltwater fish in the QT and observe them daily. Feed them and clean the tank. DO NOT put sand in the QT. All you need is a bare saltwater aquarium. This will make it much easier to vacuum to remove the uneaten food and fish waste and the ich parasites will not be able to encrust in their shells if there is no sand.

You will dose cupramine to your saltwater aquarium quarantine tank to treat your saltwater fish for ich.

Cupramine is a copper solution by Seachem and it kills ich parasites.

When the ich parasites leave the bodies of your saltwater fish, they will be killed by the copper in the water.

Be very careful when dosing cupramine, as it is toxic to fish at high levels and will kill them. Cupramine acts as radiation therapy, if you will, to kill cancer. For this reason, I dose half the recommended dosage of cupramine, which is enough.

There are cupramine test kits to test for the levels of copper in your saltwater but these tests are not accurate and impossible to read. For this reason, I dose a little more than half of the recommendation and it works great.

Cupramine will kill inverts such as snails, star fish, crabs and coral. DO NOT put cupramine in your main saltwater aquarium for this reason.

After 6 weeks you can remove your saltwater fish and place them in your main saltwater tank.

QT saltwater aquarium setup for coral and inverts


  • Quarantine each new fish in your 2nd saltwater aquarium (QT) for 6 weeks before placing in your main saltwater aquarium.
  • Always buy dry rock off the shelf from the local reef store and not live rock.
  • Live rock is in the water of your local reef store and that water can be contaminated with ich parasites.
  • If you want to buy live rock, keep it in a separate QT for 6 weeks.
  • When you buy coral or inverts you should QT them as well for 6 weeks in a 3rd QT tank with NO COPPER!
  • The reason for a 2nd QT for inverts or coral is you can’t risk any copper residue killing these living creatures.
  • I have 2 QT’s….one for new or sick fish and a 2nd for new coral or inverts I want to buy.
  • Some people always keep a 2nd QT running in case they need it.
  • DO NOT cross contaminate equipment from your QT that may have ich with your main saltwater aquarium
  • Ich can be killed with fresh water – I make sure to submerged all nets, vacuums, hoses in freshwater that were used in my QT tank to make sure there is no ich on any equipment. Submerge for 2 days minimum.
  • Fresh water will kill ich within 24 hours.

For an effective quarantine, the new inhabitants must be kept for a minimum of 6 weeks in a separate aquarium. Don’t waste your time if you can’t commit to this.

DO NOT put ANYTHING in your main saltwater aquarium until it has been quarantined for 6 weeks in a separate saltwater aquarium!

Quarantine and treat the infected saltwater fish and any other potential hosts while allowing the display to go fallow (without any fish) until the ich pathogen or pest population dies out: 6 weeks minimum.

In some cases, like Cirolanid isopods, three months may be required.

Copper (copper sulfate/copper citrate/ cupramine): Copper is a metal ion which is also basically a poison to any organism at a high enough concentration.

Copper treats most external protozoan and flatworm parasites. It is not very effective against crustacean parasites (parasitic isopods/copepods and the fish lice argulus/branchiurans) or marine leeches.

Copper is generally run at .2 ppm and only the salifert test kit we have found for the hobby level can accurately tell you where the levels are at within a respectable range. (API, red sea, Seachem don’t seem accurate enough or the colors are too close.)

Remember, it is very hard to test for cupramine / copper levels in your saltwater aquarium. For this reason, it is recommended to dose a little more than half of the suggested dosing on the label.

Fish in general become lethargic and anorexic around .4-.6 ppm with copper sulfate and copper citrate and around .6 -.8 for cupramine.

Some fish, such as seahorses/mandarins/lionfish/dwarf angelfishes/any already stressed or sick fish, are hypersensitive to copper, though some saltwater aquarium hobbyists have reliably treated those species with cupramine.

A very important note: Do not use ammonia binding compounds (amquel/prime) or UV sterilizer with cupramine and so it is imperative to turn those off when treating.

Copper overdoses include lethargy (fish acting dull, agitated, and unresponsive) anorexia (fish not eating), and even neurological signs like blindness. Another important warning when using cupramine is that dosing directions on the bottle are not clear about the therapeutic dose. They explain dosing in terms of what volume to add to get to .5 ppm, however this dose is not necessary and actually getting close to a dangerous level for some fish. Therapeutic levels to treat most protozoan parasites is .2 ppm so cupramine should ideally be kept around .25-.3 ppm.

Thanks for reading. If you have any questions let me know.

Visit my Saltwater Aquarium channel on YouTube, Rotter Tube Reef.


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