Due to the skittish nature of platies, they do like to hide in their aquariums and it can be normal for a platy to hide in their tank for a couple of hours each day.
However, if you platy is constantly hiding behind the filter in your aquarium, it could be a sign that something is wrong with the fish.
The most common reasons that a platy will hide behind its filter include the platy being stressed, anxious, pregnant, sick or is trying to submit to the dominant platy in the tank.
If your aquarium is a community tank with multiple fish species then aggression from other fish may cause the platy to hide behind its filter to try and get away from larger fish.
Although platies do like to hide, it can be dangerous to for a platy to hide behind the filter in its tank. If the platy gets stuck behind the filter, it could die from lack of oxygen.
If your platy is hiding behind its filter, make sure to check on the fish regularly to ensure it is not in danger and most platies should move to another location in the tank after an hour or so.
Is It Normal For A Platy To Hide Behind The Filter In Its Tank?
Platies are skittish by nature and do like to hide in their aquariums. It is normal for a platy to hide in their tank for a couple of hours each day. If your platy is constantly hiding behind the filter in your aquarium, it could be a sign that something is wrong with the fish.
As we covered in our article going over platies hiding in the plants in their tanks, platies can hide in a wide range of strange places in their tanks.
In addition to that, platies can hide excessively (for more than a couple of hours per day) for a wide range of different reasons making it difficult to work out exactly what’s wrong.
Thankfully though, with a little bit of investigation, you should be able to work out the problem and help your platy find a better hiding spot in your tank to help it meet its urge to hide without the risks of it being so close to a filter.

Why Do Platy Fish Hide Behind The Filter In Their Aquarium?
There are a number of reasons that a platy may hide behind the filter in its aquarium including stress, anxiety, illness, pregnancy, submission to the dominant fish in the tank, aggression from tank mates, and the platy being in a high flow tank and trying to get out of the water flow.
The most common causes of stress and anxiety in platies include, but are not limited to, a sudden change in water parameters (pH, temperature, hardness), a change in tank mates, over crowding, and a lack of hiding places in the aquarium.
Platies like to have a lot of plants and decorations in their tanks so they can hide when they feel stressed or threatened and unfortunately, this includes behind their filter.
You can usually see the signs of aggression from other fish towards your platy as the platy will be hiding more than usual and may have fins and scales that are ripped or missing.
Platies are also known to hide when they are pregnant as they are trying to protect their fry from being eaten by other fish in the tank.
Is There A Way To Prevent A Platy From Hiding Behind The Filter In Its Tank?
There are a few things you can do to try and stop your platy from hiding behind the filter in its tank. The first is to provide the platy with plenty of hiding places in the form of plants, rocks, decorations, and driftwood.
You can also try to increase the number of platies in the tank as platies are social fish and do like to be in groups. This can help to reduce the stress levels in the platy and make it feel more comfortable in its environment.
Another thing you can do is to try and reduce the water flow in the aquarium as platies are not fans of strong water currents. You can do this by either using a smaller filter or adjusting the flow on your current filter.
You should also make sure to keep an eye on the water parameters in your platy’s tank as sudden changes can stress the fish out and cause it to hide. Platies like their water to be between 72-78 degrees Fahrenheit with a pH of 7.0-8.0.
Finally, you should try to avoid overfeeding your platy as this can lead to health problems and stress. Feed your platy 2-3 times per week and only give them enough food that they can eat in 2 minutes.
Is It Dangerous For A Platy To Hide Behind Its Filter?
While it is not dangerous for a platy to hide behind its filter, it can be if the platy gets sucked into the filter. This is why it is important to make sure the flow on your filter is not too strong and that you provide the platy with plenty of hiding places in its tank.
We have seen a number of reports on social media about platies that have ended up stuck in the intake valve in their tanks filter and sadly, most of these platies have died.
Even if your platy does survive being stuck in the intake valve of its filter, its injuries can still prove fatal over the coming days.
To prevent this from happening, you should check the intake valve on your filter regularly to make sure there is no debris or platies blocking it and you should also make sure the flow on your filter is not too strong.
What Can I Add To My Tank To Stop My Platy Hiding Behind Its Filter?
There are a few things you can add to your platy’s tank to try and stop it from hiding behind its filter. The first is to provide the platy with plenty of hiding places in the form of plants, rocks, fish hides, decorations, driftwood, and even ceramic objects that are aquarium safe.
In some cases, especially if you only have a small number of platies in your tank, adding additional platies of the same species can help to reduce the stress levels in your platy and make it feel more comfortable in its environment.
This can help your platy feel safer in its aquarium and stop it from trying to hide behind the filter in its tank so much.
As platies will commonly want to hide in their tank for a small part of each day, you will often find them hiding in the alternative hiding spots that we listed above rather than behind their filter once the alternatives have been added to their tank too.