Light sensitivity?

[FatCat]

Hello might seem like a stupid question but lots of smart people here so i figured id get a good answer. Are catfish actually sensitive (as in causing pain or discomfort) to bright light or do they just prefer it dark. From what ive seen some are more acustomed to the light than others is this true also? Is eye size an indication of sensitivity? ive noticed that samller eye fish are hardly ever seen with lights on. What is an acceptible standard of light that most catfish will come out into (watts per galon?) im currently using 30 watts flourescent in 60 gallons, not enough to sustain plantlife but still more than the cats will come into except to grab a mouthfull and dart back into the cave.

[Silurus]

Catfish are not particularly sensitive to light...they are just adapted to the dark. In other words, their brain is hardwired so that they retreat and hide when light is present. The light does not cause them pain in any way. Eye size is not really an indicator of sensitivity. Catfishes living in dark habitats (e.g. caves, depths of large rivers) have reduced or no eyes, but that's because they have no need of eyes and the resources that would otherwise be used in making eyes are better utilized elsewhere (e.g. in growth or reproduction).

[coelacanth]

The light does not cause them pain in any way.

However, being unable to escape from strong lighting may well cause severe stress to a photophobic species, which will have a negative effect on the overall well-being of the fish. If they are unable to express normal foraging behaviour, it could well be argued that the welfare of the fish is being compromised.
Pete (with his zoo animal 'environmental enrichment' hat on)