so im getting a new bigger tank soon and i dont know what to use my smaller 20G tank for i wass gunna get a figure 8 puffer but this is gunna kinda be like a side project so the brackish water thing makes me not wanna do it. i still want somthing rele cool in there but all i rele want to do is the normal stuff like water changes and stuff like that so if there are any suggestions on what i should get let me