When i had mine, I had it straight freshwater. I fed it just feeders because thats all it would eat. It was about 7 inches and ate anything that it could fit into its huge mouth. it is also called the grunting toadfish because it makes a grunting noise that scared the sh*t out of me the first time i heard it. I had it in sand but it kicked up the sand quite a bit and the sand gets stuck in the filter so i just put in gravel and added a cave so it could hide in. And yes they are not very active at all. But it is cool to see them eat because they are lightning fast. One second their there and a fraction of a second later their gone. I had the ph neutral 0 am, 0 Nitrite, and it did good in these conditions. hope this helps.