AquatopInternal Sponge Filter for Aquariums – Suitable for Tanks Up to 25 Gallons, Freshwater and Saltwater Use, Compatible with Air Pumps or Powerheads

2 stage filtration which is better than most sponge filters. It’s also very cute

I do nano bowls/tanks and these are my go-to filter. They fit in the palm of your hand and do a great job.

I love these filters! They are the only one I use in all 26 of my tanks! I have several of each size. You won't be disappointed.

This sponge filter is excellent. I love how easy they are to maintain and they keep the tank healthy. It's a nice size and isn't too much of an eyesore in the tank. I prefer them to the other kinds of filters out there. However, I didn't give 5 stars because THE AIR PUMP IS AWFUL!!!! I have gone through, no joke, 5 of these in one year. Good thing there kinda cheap. But you hook the air pump up and it's quiet for ehh maybe a week and then it gradually gets louder with this obnoxious hum that fluctuates in volume. I've tried putting padding underneath to keep it from rattling and moved it. This sponge filter would be incredible if the air pump was better in my opinion.

I used it in conjunction with my marineland filter to keep my aquarium clean and fresh

Looks like the picture and works fine. Hooked onto a power head and filters well

I have a 5.5 Gallon Aqueon tank that houses Amano Shrimp and a Tiger Nerite Snail. The snail loves to sleep in the corners where the bubbles flow and the shrimp love picking off stuff from the sponges. I have two in the tank due to I needed a second one for it's compartment to help with an ammonia issue I was having, now that I've taken care of that, the second filter will be used to seed future tanks.The compartment is probably my favorite part of this sponge filter. Not only does the sponge hold the beneficial bacteria, the compartment can hold small filter medium for additional BB storage. That or if you're having an ammonia spike, add Zeolite to it to help with that.My only issue with this sponge filter, with out a two sided suction cup, the filter doesn't seem to want to stay put, even with small pebbles/zeolite in the compartment.

It's hard to find sponge filters for smaller tanks since a smaller sponge means less filtration which is the intention here. It's not that large sponge filters won't work in a 5 gallon fish tank but that they'll be intrusive, taking up valuable space for plants, fish, and invertebrates. In this case, this sponge filter fits the bill for nano fish tanks. It does need to be saturated with water for it to sink, though, so be sure to squeeze the sponge as you put it in your tank. Otherwise, it's easy to clean and use.