Looking for the spotlight: Do your fish notice the lighting in your reef tank?

[Peace River]

Looking for the spotlight: Do your fish notice the lighting in your reef tank?

When we think about the lighting in our tank, we are focused on how it affects our corals and what it looks like to us and not how it affects our fish. Sometimes the environmental factors in and around our tank do impact the behavior of our fish. For example, certain fish may be affected when the tank is in a high-traffic area. Similarly, I have had freshwater fish that stay in the shadows of the tank and others that rarely leave the cover provided by structures within the tank. What about your reef aquarium – do your fish notice the lighting in your reef tank? Do any changes in lighting change when and where they swim. Sometimes the fish will eventually get used to the change and return to their previous behavior and other times the impact will continue. Additionally, I have seen fish notice the light shimmers and even seem to “play” in the light flickers. Tell us about your experience with observing the interaction between your fish and lighting in your reef tank!

Photo by @Jeffcb


This QOTD is sponsored by: www.topshelfaquatics.com

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[JGT]

Before lights on in the morning, my fish tend to just hover in place. Once the lights come on, they start actively swimming. At night, as lights go down, they retreat to their sleeping spot for the night.

 

[Gumbies R Us]

Before my lights are on? My watchman goby freaks and swims away when I reach the tank. Lights are on? The watchman will stare at me. My clowns however don't act too much differently with the lights

 

[SnazzyUrchin792]

I’ve noticed the room lights affect the behavior of my fish. Depending on what else is going on in the room with my fish, my valentini pufferfish will usually wake up 1-2 hours before the tank lights come on and stay up 1-3 hours after they turn off. However, he is skittish and stays close to the sand until the lights come on. He will typically go to sleep on top of my magfloat when all the lights are off. The starry blenny and YWG hide in the rocks when the tank lights are off. The clownfish pair is completely unaffected by lighting.

 

[kenchilada]

I run an aquarium for the blind so we’ll never know

 

[vetteguy53081]

My fish have ambient light from glass as I have so much of it in the living room and right after lights are on, the auto feeder drops food at cycle #1

 

[shakacuz]

i'd like to assume they're used to the light cycle and somehow come out right as the lights are about to ramp on, or transition to their hides as the lights ramp down.

 

[Johnd651]

Voted other. I never see them notice the lighting, but I tired a different light yesterday on my FW tank for a second and I never seen them school up as fast as they did.

 

[Doctorgori]

yeah certainly those red cardinals do, the Pacific types simply wait until dark, the Florida type likes dusk/dawn settings

 

[JayM]

Aside from normal hunkering down when the lights start to dim, and waking when they start coming on, they all hover around the feeding spot when I turn on “feed mode” as I have the lights set to a different color spectrum at that time. They know it’s time to eat when the lights go bright.

 

[jvbear]



Before lights on in the morning, my fish tend to just hover in place. Once the lights come on, they start actively swimming. At night, as lights go down, they retreat to their sleeping spot for the night.

mine do this too

 

[Treefer32]

I have a black long nose tang going on 10 years old (I've had him 9-10 years). My understanding is these are deeper dwelling fish which makes them rarer and much more expensive to have. Mine black tang fights for spots under corals and hovers when my lights are the brightest in those spots. Then swims out to peck at rocks then returns back to an overhang or coral shelf and sits there waiting for the lights to go to their dimming cycle.

All of my fish and corals know about 2-3 hours in advance when lights will start dimming, my corals close up when it seems like the lights are still bright. But open right back up in the morning of the next day. The fish follow this trend as well. I once had a LFS tell me that many corals stick feeders out at night because that's when fish poop the most. I don't know if there's any truth to fish poop in the dark. My fish poop plenty of times during the day. I would say it tends to be later in the day, but it's also when I feed the most. So....

But yes, fish tend to play with the lighting and act like they are unsure if they want to be seen at times, especially smaller fish when I have much larger tangs. Its a constant game of hide and go seek. My Caribbean blue tang likes to remind the fish that the tank is his. He leaves the other tangs alone, but swims by all the hidey holes checking that all the smaller fish are submissive to him.

 

[BAMslam93]

Haha my clownfish pair know the light routine; once the lights start dimming they go to their normal bedtime spots. My girl loves sleeping in the pvc pipe on the rock and my boy likes hovering in a corner between my powerhead cable and glass

 

[Reef Psychology]

If I change my light schedule the wrasses that dig change their wake/sleep schedule after a few days.

 

[vlangel]

My fish respond to waking up and going to bed. That is about the only thing I see them react to but I have an LED that ramps up and down very slowly from 5am til 9pm.