Freshwater lighting should be 6500k or less.. Freshwater Plant growth uses 6500k or less, and anything above that is just wasted lumens. It also fuels erranous algae growth, including black algae which can be very problematic. This is the biggest concern with using the wrong spectrum and intensity bulb on a freshwater tank. Especially with Oscars who often have a higher nitrate level, look forward to a horrible algae epedemic.
As far as your oscars sulking, it's very common, especially with Actinic lighting on freshwater fish. I have also read reports that it can damage the vision of the fish, but I believe that was more oriented for using black light. I have also heard that running straight actinics with no other white lighting can cause stress issues, especially for freshwater fish.
Think about it like this.. How much light intensity do reef dwelling fish get, in their crystal clear water? ALOT... Now Oscars, who come from the muddy, dark waters of South America, probably won't appreciate such intensity. Ever wonder why Cichlids have such AWESOME vision in the home aquarium? It's because they have adapted to predate in dark murky waters, and once in a clear aquarium their vision is that much more enhanced. (African Cichlids fare much better with higher intensity bulbs, due to their natural environment in the rift lakes.. clear water, etc.)
Did you compare the prices between the Marine-Glo and the other Freshwater bulbs? If I recall the Marine-Glo is one of the more expensive products, and the owner might have been trying to make his sales goal that today. Sounds like hes taking advantage of his status, or is just an ignorant dolt.
Take it back..
Could someone tell me if it is safe or not? Thanks!
