Filters? (camera accessory not tank fixture)

[Der_Iron_Chef]

Polarizer is the single most useful filter you can buy! Some might disagree, but....well....they're just wrong

As mentioned, a polarizer will minimize glare off reflective surfaces (glass, water, etc.), and will make colours/contrasts much more dramatic (a cloudy sky taken with a polarizer is much more appealing than without, for example).

Git it!

[Delphinus]

Polarizer! .. Wait, I already said that. But I thought I'd say it again since you asked again.