Plecos are known for their sometimes shy behavior. Maybe you just bought a pleco and notice that it primarily hides.
I’ve had such a pleco. It was hiding all day and only at night, it would dare to come out. This makes many people say these fish are nocturnal. But are they?
Are plecos more active at night?
In normal circumstances, plecos are not more active at night, because plecos are not nocturnal. If your pleco is not active during day hours, it might be stressed and not feel comfortable.
Are plecos nocturnal?
Unlike popular belief, plecos are not nocturnal fish. They are diurnal like many other fish species, which means they are the most active during the day. Plecos are often thought to be most active at night because they tend to hide a lot during day time.
Unfortunately, there is a lot of misinformation on this topic. Because there aren’t a lot of resources on this topic, people have just been guessing that plecos are nocturnal.
The most commonly used argument to claim that plecos are nocturnal is because when not fully comfortable, they tend to hide during the day. This can be because of various reasons, such as not enough hiding places or wrong tank mates. I’ve actually written an entire article on why plecos hide and how to get them to be more active.
At the same time, people see that their pleco might come out when the lights are off. This is however not because of its nocturnal characteristics, but because it is usually calmer at night with fewer other fish or movement in the room.