Can fish see in the dark?

[KevG]

I have cats so I keep my tanks covered at night because the cats can deffinetly see in the dark and I have caught them smaking the tank. So I put the covers on then turn off the lights and reverse in the morning.
The build up with the cover seems to let the fish know what is coming.
There is nothing wrong with turning them on or off 'on-shot' but I find a little warning is a nice thing to do
I do have timers set up on both my tanks so if I'm not around they keep a regular wake/sleep pattern.
Also specific light or photo period is important on so many levels like controlling algae blooms.
The only 'dumb' question is the one not asked.

 

[EOD]

:rofl:

 

[RiVerfishgirl]

my fish running into the tank in the dark...prob not ever. Me running into the tank in the dark. Done it and will prob happen again.

:rofl:

Yeah...I have that problem.

I've seen fish run into the side of tanks because they were startled, but that's with the lights on. With the lights off they're most likely to just go to sleep or calmly float around the tank. There are some fish (arowanas for example) that are MORE likely to run into the tank with the lights ON because they can see more and there's more to startle them into running into the tank. But I've never heard of fish running into the tank because they can't see in the dark. They're physiologically built to be able to detect things in front of them because most freshwater fish don't live in high clarity water, or at least not year round. If they had no way of detecting things in muddy water they'd run into stuff all the time.

But, just as a suggestion, if you'd like to use the tank as a night light, you can add an LED moonlight, which will provide a little light for your room, but not enough to keep the fish awake. They're also good for being able to view nocturnal fish that aren't out much during the day. You can either buy a strip of them or a pendant, or you can even make them yourself if you're into DIY stuff.

 

[EOD]

Great idea. Thanks

Posted on mobile.aquariacentral.com

 

[wespastor]

KevG hit the nail on the head with hit comments about questions.

I learned a similar quotation; it goes like this:

There is no such thing as a stupid question;
because it is easier to deal with stupid questions,
than the catastrophie created by the question not asked.

Imagine this hung on a sign in 4 inch high letters in red on the wall of a fire department near the fire engines.

I was an EMT then.

Best wishes,
Wes

 

[FGS_Flying_High]

IME fish like all other creatures need sleep. I left the lights on my Bettas on for a couple of weeks once, not thinking about them needing to sleep and I noticed that they were all acting a little strange and after putting them back on an on/off schedule they all went back to normal.