leaving the light on
- Thread starter tankbusterlover
- Start date
A rest is as good as a sleep, to a tired fish. 
Interesting to learn new stuff... i knew about the botte noses but not the rest...
Anyway, i wonder if in those tests there was any decor in the tanks or were they quite bare like the OP's???
Coz without much cover or shade i wonder how much that might effect them stress levels wise?
I think we humanize animals too much. I am not saying to leave lights on constantly, but at the same time it's probably not accurate to say they need a dark period either.
Many discus breeders, especially years back, ran 24/7 lighting in at least grow out tanks and presumably this was advantageous or there would be little reason to spend money on power.
Without any data one could also make the argument that 24/7 lighting is actually beneficial to the fish.
So thank you for the post showing the variations in sleeping!
The only advantageous thing about leaving lights on 24/7 for discus breeders, is so that the fishes feeding schedule could be ramped up, which equates to faster growth. That's it. That doesn't equate to being advantageous for the fish, only the person selling the fish when they reach market size.
In nature all tropical fish follow a day/night schedule, so it seems logical that this should follow in captivity. That's not humanizing fish, that's just using common sense.
In nature all tropical fish follow a day/night schedule, so it seems logical that this should follow in captivity. That's not humanizing fish, that's just using common sense.
Common sense would seem to dictate that matching wild photoperiod is acceptable, but not 100% that it is the ideal. Unless someone can provide data showing how variations of photoperiod effect fish I don't think there can be an answer of what is best and even how best is decided (growth, color, longevity, injuries)
Clearly breeders are motivated by growth to sell -- is that 24hr lighting interrupting the fish's sleep at all? Is it harmful? Is there increased mortality at expense of growth, or is there a decrease in mortality? Long term effects on the fish? We can't assume not matching the wilds photoperiod is always harmful, it very well might be helpful.
Anecdotally with breeders using 24hr lighting through developmentally critical time periods of a somewhat sensitive fish it would stand to reason that realistically there probably isn't a great deal of phenotypic effects seen.
Clearly breeders are motivated by growth to sell -- is that 24hr lighting interrupting the fish's sleep at all? Is it harmful? Is there increased mortality at expense of growth, or is there a decrease in mortality? Long term effects on the fish? We can't assume not matching the wilds photoperiod is always harmful, it very well might be helpful.
Anecdotally with breeders using 24hr lighting through developmentally critical time periods of a somewhat sensitive fish it would stand to reason that realistically there probably isn't a great deal of phenotypic effects seen.
Of course following the natural photoperiod of an organism is the most logical conclusion, unless of course someone can prove otherwise. What's best, or harmful, or whatever, who knows? I just didn't understand using a term such as humanizing, when what was being advocated is simply a natural act for most ornamental species of fish.
Do you drop temperatures in your tanks and cut feeding six months a year to stimulate winter for your fish? Do you think you should?
Yes, it is probably better to give your fish a more natural light cycle. It is also almost impossible unless you either have a dedicated fish room or a cabinet that you can close around the tank to block outside light.
The only outcome that I can see gaining from this thread is from the articles
Drstrangelove
posted that show that some fish do something similar to human sleep, and that it varies according to species, and a bunch of other factors, and that even human sleep is very poorly understood. I understand that you have very high standards for the quality of life of the fish you keep, and I understand that without knowing any better the best you can do is imitate the fish's natural environment as closely as possible, but I feel that in this case there is no reason to say that for a given fish lack of a proper daily cycle will effect it in any quantitative way.
I don't have a natural sleep cycle, so why should I let my fish have one?
This isn't a Q&A about what I do, or don't do. And the correct term is simulate, not stimulate.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4927530/
Photoperiod has been considered as one of the most important growth promoting factors in several fish species, it affects not only feeding behavior but also physiological condition.
In some species, including barramundi Lates calcarifer (Barlow et al. 1995) and gilthead sea bream Sparus aurata (Tandler and Helps 1985), extending day length increases larval growth and survival; however, long photoperiod regimes result in physical stress and adverse growth effects in rainbow trout (Oncorhynchus mykiss) (Leonardi and Klempau 2003).
From only a few studies referenced in this paper, clearly the photoperiod can have a negative effect on at least some species of fish. From my years of keeping fish in captivity, as well as observing fish in their native waters, this really doesn't come as a surprise. I'm quite surprised to see anyone supporting anything other a normal light/dark period. Go figure.
But just to be clear, I am only posting to assist the OP, and to answer their question, not to play the photoperiod police. If some of you feel the need to leave your tank lights on 'round the clock, that's fine by me.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4927530/
Photoperiod has been considered as one of the most important growth promoting factors in several fish species, it affects not only feeding behavior but also physiological condition.
In some species, including barramundi Lates calcarifer (Barlow et al. 1995) and gilthead sea bream Sparus aurata (Tandler and Helps 1985), extending day length increases larval growth and survival; however, long photoperiod regimes result in physical stress and adverse growth effects in rainbow trout (Oncorhynchus mykiss) (Leonardi and Klempau 2003).
From only a few studies referenced in this paper, clearly the photoperiod can have a negative effect on at least some species of fish. From my years of keeping fish in captivity, as well as observing fish in their native waters, this really doesn't come as a surprise. I'm quite surprised to see anyone supporting anything other a normal light/dark period. Go figure.
But just to be clear, I am only posting to assist the OP, and to answer their question, not to play the photoperiod police. If some of you feel the need to leave your tank lights on 'round the clock, that's fine by me.
Thanks for the spellcheck, that post was written on my phone.
Thank you as well for the reference, it is the first concrete thing anyone posted on this otherwise fascinating but useless thread.
I was not attacking you in my previous post, and I respect your opinions and expertise. I can honestly say you are one of my favorite posters on this forum and that you have taught me a lot of things. It is just your tone that bothers me, especially when you 'preach' without explaining where you are coming from.
