I have three different types of plecos and an upside down catfish in my 125. I also have a big sponge filter hidden in the back behind all the fake plants. Along time ago I found that I didn’t really have to clean this filter much because the plecos were sucking everything out of it.
I did a big rearrangement of the whole tank yesterday and I found out that these fish have been literally eating the foam from one foam filter and what was once a smooth vertical cylinder with vertical reveals is now an artistic fish-sculpture.
I have a 20 gallon sump under my 75 and I have a sponge filter in it. The 75 also has a sponge filter.
The one in the sump is covered with these tiny little snails, while the one in the tank above is not.
In fact, between hungry fish and frequent water changes, I have lost almost all the other snails in the system.
The funny thing is that these snails never get any larger. They are getting through a fine mesh on the overflow above, so maybe I am selecting for just the tiniest snails to survive?