Can fish/critters see Red light at night (2024)

I have read that the deeper you go the more red light is absorbed and becomes 'colourless' so I am not sure that they would not see it in an aquarium whereas they may not see it under the ocean. I think the depth in question is about 20ft. Dont quote me on this though I am only recalling what I think I read!

To a point yes, has been scientifically confirmed that at least some reef fish can detect red light.

I'm pretty sure my marine & freshwater fish can see red light based on their behaviour, the inverts may be a different though as they dont seem to respond to having it shone at them.

My tangs respond to red light, but inverts etc have zero response ... would be nice to have a proper answer on this.

Im using a red led bike light.....My fish and peppermint shrimp definitely change behaviour when they see it, the dimmer the light is the less they react!

I found the best way to carch a rogue crab is with a very very sharpe knife as every crab in my tank have been as super breed that do not fall for the glass trick

Yes they can and no they can't.
If you are talking about the ebay red leds and torch light then i'd say yes.A m8 had the ebay reds over his tank and the animals obviously reacted to the light.
I've got aquaray red leds over my 4ft tank and my answer on these is no they can't see the light.I say this because the fish go into sleep mode and the nocturnal critters such as pistols,peppermint shrimps, act like there is no light on at all.Plus things like amphipods become active and feed out in the open off the rocks.Since i bought this light it's the first time i've ever seen my hitchhiker pistols,i have three of them,interact with each other.I never see them if there is even a hint of daylight.I've now started feeding my suncoral by night as it opens fully about 10 mins after the aquaray red is turned on as the only light source.

Defo- my peppermint shrimps run and hide soon as i shine a brakelight off a bike on them1

I would like to weigh in on your discussion regarding can the fish see red light. I would have to say yes. why I think this is simple, in my tank I have several varieties of fish, plus shrimp and crabs. I play with them all the time with a red laser pointer; and all in the tank chase after that red dot, shrimp and crabs included. now if they couldn't see red light they wouldn't be enticed by that by that red laser pointer.
Get you one and try it out.