I have a 20 gallon, with lid. I heard that having a filter bugs them too much? I have been changing the water every 2-3 days. Since their food sinks to the bottom, I worry that if I put large river stones in, the food will just settle between the cracks and they wont be able to get to it.

I didn't want to put gravel on the bottom, because I know they'd eat it on accident. I thought about having no substrate, but doesn't the bacteria need something to cling on? And hides and plants anchored down with it?

Thanks for your help!!