Generally there are two ways of experiencing underwater fluorescence, either with invisible (ultraviolet) or with visible (usually blue) excitation light.
In the case of ultraviolet excitation light (with wavelengths <400 nm), no filters are needed for your mask and camera. You may need a “Wood’s Glass” type of excitation filter on your torch, though, in case you use a torch with white light (or a strobe), which should have lots of output in the ultraviolet range of the spectrum, such as HID (high intensity discharge) lights.
The same can be done with a white light (or strobe) and a blue excitation filter in order to obtain a blue excitation light, by the way.
However, using a white light in combination with an excitation filter that will throw away most of the torch’s light output is not as efficient as using a torch which has the desired range of wavelengths in the first place.
If you have any questions, comments or suggestions – PLEASE don’t hesitate to contact us.