Yes colour and brightness will, in some cases dramatically, change the colour of fish.

Basically this is to do with the brightness and temperature of the bulb used (the number on the box, like 6500k is the measure of the temperature). Whiter light will give a 'truer' reflection of colour. Blue lights will cool the colours while red will warm. Brighter white lights penetrate the water better so colours will be brighter to the eye. Although not noticable in most tanks (has to be a tad deeper than most home aquaria) the absorbtion of light becomes more noticeable. Red is absorbed first and blue last. So as a diver, within a few meters, red is lost completely. That is also why two bulbs of the same size but different 'temperature' light more or less of the aquarium. You would see this in very large aquaria too. Thats why their water always looks quite blue in those massive tanks.

sorry, im a bit of a geek with this. I like my underwater photography while diving. >. < so if that was tmi I apologise. You just seem interested.

 

Thats interesting information, but does small tanks have will have these effects? (mine is 2.5 gallon)

what i was guessing was the fish is trying to match the environment so it changes its color to lighter shade in white light

 

My betta Atlas is red with purple. In the dark, he just looks red.

But under lights, purple!

 

yeah I like how they look under lights better, because you can see the details, you fish is very pretty btw! He reminds me of my betta fireworks in my avatar pic lol. Goodluck!.

 

thanks a lot, he is still very small, dont know why he is know growing faster

BTW I took him home 6 weeks ago

 

Right, Mummy. 6500K (Kelvin, color temperature) is supposed to mimic tropical sun at noon. It's considered the most accurate color rendition. I've heard plants like it best.

18000K is usually used for reef and other SW applications. How's it working for you?

 

I need to double check (the box is outide and its raining) but that looked like the box when I googled it XD I thought it seemed high too, but I cannot find any evidence that my bulb manufacturer makes the 24" T5HO in 6500 D: So God only knows what I have in there! Pmsl. Must check, I was sure I wrote it down somewhere too!

 

Yes, i switched to a filament bulb from white LED.

Two benefits....

1. IT provides heat to keep water warm
2. My fish looks brighter in yellow light