NOTE: requires some cleaning and does not come with accessories (foam or carbon pads) Where do fish go when they're feeling down? To the filter for some TLC! And if you've got a 24-40 gallon aquarium, the Fluval U3 Underwater Filter is the perfect match for your aquatic buddies. This filter is like a superhero for your tank, with three stages of filtration to keep the water crystal clear and healthy for your fish, marine creatures, or reptiles. Check out its awesome features: - Stage 1 foam removes all those pesky particles that can make your water cloudy and gross - Stage 2 poly/carbon cartridge traps debris and removes any impurities that might be lurking around - Stage 3 BIOMAX provides biological filtration, which basically means it creates a happy home for all the good bacteria that help keep your tank's ecosystem in balance - The 3-way flow control lets you adjust the output to fit your tank's needs - whether you need a gentle current or a stronger flow - The Flip-Top design makes maintenance a breeze - just pop it open, swap out the cartridges, and you're good to go