Do oscars like bright light or dim light. my oscar seems to be more active in dimmer light.

Aquarium lights are really only for our benefit. The majority of habitats are not brightly lit like your aquarium. Many waters in the Amazon are very murky and dimly lit, this is where you'll find Oscars.

obviously it's nice to be able to see the fish, but do bear in mind that they might not like too bright.

Not much to add to that except that your fish will soon get used to your tank being lit up

I run two 10w submersible lights on the sides of my tanks.

They aren't in the water, just chose that type because the ballasts are outside the tank and are easy to replace. These two lights are on a timer, since I often stay over at the girlfriend for a weekend or so and like to keep the little guys on a schedule.

They are however only about 40cm long, meaning they only really heavily light up one side of the tank.

Then I have a single 30W T8 tube, which is a 92cm tube if I recall and also doesn't quite cover the entire length of the tank so they still have a darker space to chill if they want. This light is on a manual switch and I turn it on when I'm around for extended periods of time.

Although they don't particularly freak out when the 30W is on, and still swim in that section of the tank, they seem a whole lot more at ease when only the 2 x 10W's are on.

So ultimately what I'm saying is don't overlight the entire Oscar tank, and you should quickly note their preferences.


Also in the past I have learned Oscars freak out when lights are suddenly turned on, or off for that matter.

When my previous pair were in the tank next to my bed, they would actually make a wave that would run over the lip of the tank, and splash me during the night...I swear they did this on purpose, because it only ever happened when I suddenly came into the room put light on and then off, and turned their tank light off at the same time.

If I gradually turned lights off, starting with the main room light, then a few minutes later the main tank light, then later the secondary dimmer night light, and eventually the bedside lamp then they would never cause any trouble.