Sunlight

For about an hour in the evening, the sun catches a corner of my mbuna tank. As the fish pass through this part of the tank, the colours of the fish are incredible, so different to the colours under "normal" aqaurium lights.

Question: Do artificial lights reproduce the same effects as natural sunlight??????

depends on the bulb used really the sunlight bulbs can reproduce this to an extent, the marine blue lights can emphasise blue colouration and others with different spectrums enhance other colours, but none imo can truely capture sunlight the nearest i have seen is the newer high end LED lights which produce a water shimmer in the tank and look fantastic

This is a very similar question that we often get with reptiles.

Line up in a 400 meter hurdles race (I was once a 400m hurdler )the Sun, the best artificial light, good artificial light and really crap light.
At the starting gun.....
the crap light is still in the dressing room;
the the good artificial light looks really good as it pushed from the starting blocks;
but the best artificial light has already cleared the first hurdle....meanwhile...
the sun is sitting down doing not much at all except drinking some isotonic fluid.

....the sun had hit the finish line, done its lap of honour before the others had cleared the first hurdle.

When comparing artificial lighting to the sun, it is a completely different league and is a bit unfair on the superb artificial lighting systems that we do have.
I have high intensity mercury vapour UV lamps as well as normal fluorescent lighting.....the mercury vapour lamps are by far top of the league in the artificial lighting systems, but are not in the same league as the sun.
If I give my chameleons a few hours outside in the sunshine.....that will effectively be equal to 12 hours per day everyday for a month worth of fluorescent tube lighting.

Many fish, plants, reptiles, amphibians don't just rely on that 'midday' fixed spectrum from the sun.....the sun is not fixed.

For the physiological health of species, artificial light has done great work in simulating the parts of the sun required for the minimum biological needs of plants and animals....but they don't always do a great job in stimulating psychological needs or activity pattern changes.

Apart from certain wavelengths missing from artificial lighting, the relative intensities and angle of light need to be looked at.

Early morning sunshine is a great light for some species of fish, plants and frogs (I use early morning and late evening sunlight to stimulate dart frogs into spawning; and early morning sunlight is often great to get some fish to spawn).

As for colours in fish....many blues are an optical illusion from guanine crystals (a bit like blue eyes in humans)....the colour is not actually there, but the angle of light falling on the crystals and the angle of observation will change the blue. So if you have a more 'shear' light striking acrossways, you may get more diffraction and more intense colours.
In speculating, the other fish may observe such intensity and change their behaviour in response to seeing a more brilliant blue (but that is only speculation as we don't rally know if the others will see that increased or, maybe decreased in water, intensity).

ian

I've said it before; Mother Nature will win every time!!!