Leaving small blue/black led and red volcano on all night

Biglog

New Member
Joined
Apr 14, 2021
Messages
58
Reaction score
7
Location
South Carolina
I have a small led light strip in one corner of my tank that is set to come on at night when the main lights go off and a red led volcano airstone on all the time. After reading some articles it seems there are mixed opinions on whether it is ok to leave these lights on at night or if the fish need total darkness. Here is the led light I have https://www.petco.com/shop/en/petco...PM_GGL_Evergreen_FreeShoppingListings-_-0-_-0 and it’s in a 29 gallon tank for reference
 

PheonixKingZ

Fish Guru
Tank of the Month!
Pet of the Month!
Fish of the Month!
Joined
May 8, 2019
Messages
15,103
Reaction score
8,913
Location
Lawrenceburg, KY
I read somewhere that fish can’t see the red light so would that be ok?
Some research has been done that if fish can distinguish between red and other colors, but I’m getting conflicting answers.

I would just leave it off. If you had guests coming at night, then I would leave it on, to show off your tank. ;)
 

Byron

Fish Expert
Joined
Feb 25, 2009
Messages
14,630
Reaction score
6,049
Location
CA
In fish, as for most animals the primary receptor of light is the eye, but other body cells are also sensitive to light. Most animals have an internal body clock, called a circadian rhythm, which is modified by the light/dark cycle every 24 hours. Our eyes play a primary role in this, but many of our body cells have some reaction to light levels. In fish this light sensitivity in their cells is very high.

Fish eyes are not much different from those of other vertebrates including humans. Our eyes share a cornea, an iris, a lens, a pupil, and a retina. The latter contains rods which allow us to see in dim light and cones which perceive colours; while mammals (like us) have two types of cones, fish have three—one for each of the colours red, green and blue. These connect to nerve cells which transmit images to the brain, and the optic lobe is the largest part of the fish’s brain. The rods and cones in the eye shift according to the changes in light. This process is also anticipated according to the time of day; the fish “expects” dawn and dusk, and the eyes will automatically begin to adjust accordingly. This is due to the circadian rhythm.

These cells are very delicate; humans have pupils that expand or contract to alter the amount of light entering the eye and eyelids, both of which help to prevent damage occurring due to bright light. Fish (with very few exceptions such as some shark species) do not have eyelids, and in most species their pupils are fixed and cannot alter. In bright light, the rods retract into the retina and the cones approach the surface; in dim light the opposite occurs. But unlike our pupils that change very quickly, this process in fish takes time. Scientific studies on salmon have shown that it takes half an hour for the eye to adjust to bright light, and an hour to adjust to dim light.

There must be a continuous period of several hours of total darkness--no tank lighting and no room lighting--during each 24-hour span. How the fish react to this expected period of darkness depends upon the species.
 

Sgooosh

Fish Gatherer
Joined
Dec 3, 2020
Messages
2,877
Reaction score
1,005
Location
United States
Some research has been done that if fish can distinguish between red and other colors, but I’m getting conflicting answers.

I would just leave it off. If you had guests coming at night, then I would leave it on, to show off your tank. ;)
hm, i think they do, my guppies follow the laser pointer when i test the temperature like a cat

so distant
yet...
so similar
 
Top