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How To Treat Guppy Flashing Quickly!

With guppies being such a commonly kept species within the fish keeping hobby, we see a wide range of different questions from the fish keeping community about the various problems that they have with their guppies every month.

One thing that does seem to be increasingly common is people having problems with guppy flashing even when there are no visible problems with the fish other than constant itching so we wanted to publish this article to try and help as many of our readers as possible.

It can be normal for guppies to itch throughout the day for short periods of time but if your guppy is consistently itching then it is usually an indication that the fish is having problems with parasites or poor water parameters.

Thankfully, both of these are usually easy to treat and noticing your guppy flashing by constantly itching early enough will usually let you treat the issue before any long term problems can develop.

There are a number of less common causes of guppy flashing but they really are rare.

The only less common cause that is usually worth looking out for in your own guppies is damage to the scales of the fish due to injury with the rest being so rare that it is usually a waste of time even looking for them due to parasites such as ich and poor water parameters being such a common problem.

What Is Guppy Flashing?

Guppy flashing is a term given to a guppy that is constantly itching itself against something in its tank. This can commonly include the substrate, tank decorations, rocks, and in some cases plants if there is nothing else available for the guppy to itch against.

If left untreated, guppy flashing can result in serious problems with the fish due to two problems developing.

The first is that the fish has something causing it to itch with parasites and issues with its water parameters being the most common with both potentially being fatal so they need to be investigated and corrected.

The second is that constant itching by your guppy will eventually weaken its scales and potentially damage its skin.

Although a guppy itching for a week or less is unlikely to cause this type of damage, guppy flashing over an extended period of time can easily result in serious problems with the fish due to the excessive itching so you really do have to treat the issue as fast as possible.

Why Are My Guppies Flashing?

The two most common problems in an aquarium that can cause guppies to flash are problems with various external parasites and issues with the water parameters that the fish is living in.

Parasites will often have visual cues on your guppy giving you an indication of the problem but water parameters will usually need a water test kit to confirm the issue.

You can keep an eye out for secondary symptoms of poor water parameters such as clamped fins in your guppy and visual clouding in the water but this usually takes time to develop.

Ideally though, you really should have a decent water test kit to monitor the water parameters in your tank.

They only test a couple of dollars more than the normal test kits but are far more accurate and offer more insight into the potential issues in your tank causing guppy flashing.

It is becoming more and more popular to acclimatise guppies to saltwater or brackish water these days and although this is relatively easy to do with the correct equipment, people often rush the process.

If you are keeping your guppies in saltwater and notice that your guppies start flashing after being put into the new tank then it may be due to the fish not having been acclimatized correctly.

How To Treat Guppy Flashing?

It is usually very easy to treat the common causes of guppy flashing and a water change may be enough to deal with problems with water parameters that can cause guppy flashing.

If your guppy is flashing due to it having problems with parasites then you may have to do some investigating as different types of parasites require different treatments.

For example, if your guppy has white spots on it suggesting that the problem is ich then you will need something like super ich cure to treat the issue and most other treatments will struggle to deal with ich.

If you suspect that the issue causing your guppy flashing is due to a different type of parasite or fungal infection then something like Melafix should be able to treat the issue.

It can be common for people to keep just male guppies in their tank due to their brighter colors and patterns or to keep a heavily stocked guppy tank and this can encourage your guppies to fight for dominance in the tank.

This may result in injury to the fish and damage to the scales causing the guppy to itch way more than usual but this can be difficult to fix quickly but given time, the guppy can often heal by itself.

Why Your Guppies Are Flashing After A Water Change!

It can be common for guppies to start flashing after a water change if you use tap water when changing the water in your aquarium due to the various chemicals that are commonly found in tap water.

There are a number of tap water conditioner products on the market that you are able to use to reduce the levels of these chemicals.

Many people who keep guppies are new to the fish keeping hobby and may have only done partial water changes in their tank previously where the chemicals in tap water are less of an issue.

A larger partial water change or a full water change in your tank can spike these potentially harmful chemicals in your aquarium and cause your guppies to flash constantly though.

This is very common and why we see so many people respond with comments about how they have used tap water before in their tank without issue.

You usually have a very fine line between what will and won’t cause your guppies to start flashing after a water change and it can be easy to go over it with untreated tap water and cause your guppies to start flashing.


That brings our article going over how to stop guppy flashing in your aquarium to an end. We hope that we have been able to help you better understand why your guppies may be itching so much as well as how you are able to treat guppy flashing. Thankfully, it is usually a very simple condition to treat in most aquarium setups and the majority of people, even if you are new to fish keeping should easily be able to treat the condition without there being any serious long term problems with your guppies.