NICREW 53 GPH Internal Aquarium Filter

The NICREW Internal Aquarium Filter is a small in-tank filter for tanks from 5 to 10 gallons, rated at 53 GPH. It holds activated carbon and fine filter foam, and it can mix air into the water as it pumps. Four suction cups hold it to the glass.

What it filters

The fine foam traps debris and fish waste, and it also hosts the beneficial bacteria that handle ammonia. Activated carbon absorbs odors and the yellow tint that builds up between water changes. Together that covers mechanical, biological and chemical filtration in a small package.

Air and flow

An adjustable air regulator controls how much air the filter pulls in. Open it for lots of bubbles and extra oxygen, or close it down for a gentler flow. NICREW says the gentle setting is safe for delicate fish and shrimp.

Setup

• Rinse the foam and carbon before first use.
• Mount the filter low on the glass with all four suction cups.
• Keep it fully underwater while running.

It comes apart quickly for cleaning, and it works in freshwater and saltwater.

Maintenance

Rinse the foam in removed tank water when flow drops. Replace the carbon every few weeks, and take it out while medicating. Check the impeller for trapped plant bits now and then.

Who should look elsewhere

If you don’t want equipment inside the tank, a hang-on such as the NICREW slim HOB filter sits on the rim. For a fry tank with the gentlest flow, a sponge filter like the AQUANEAT bio sponge is safer still.