Feral Boy wrote:

Hi, could someone please tell me which will be the best Hagen light tube
will be best for showing the colours of my fish?

For showing colours a natural white bulb (5000 to 6000 Kelvin) would be
best. However there are other things to consider.

Do you have a fresh- or seawater tank? If seawater, your reef critters
need a lot of blue and ultraviolet light to stay healthy, and some of
them show a very pretty fluorescence. There are special "actinic" bulbs
for that, with light colour of 10,000 Kelvin and more.

If freshwater do you have plants? Plants require red and blue light for
photosynthesis, but standard tubes give little red. Thus your plants
would do better with a "tropical" broad-spectrum tube. There are also
"grow"-lights, which have only blue and red, no green. For a plant only
tank that might be acceptable, as plants use little green light anyway.
However, under that sort of light the colours of fishes would look very
unnatural.

If you don't have plants, a cheap standard white tube from the
supermarket would serve you just as well as the more expensive ones from
your LFS.