I have a couple of 2.5 gallon betta tanks with these filters. They are okay, but I'm not super thrilled with them. If these tanks would accommodate a small HOB filter, I would probably use that instead.
The HOB probably would interfere with the lid but really...unless you really need it to prevent fish from jumping or a curious cat or something like that...there's not really a great reason to use a lid. Only time I really ever try to fashion something into a lid is if I'm going to be away from home several days. A lid will help slow down evaporation. For that on my small tanks...I'd just stretch some Glad wrap across the top leaving enough room for the water coming from the filter and to make sure there was enough oxygen exchange. You don't want the tank sealed up tight.Thanks folks....I'll check out the few that were mentioned here. I thought of HOB ones, but wouldn't there be an issue with the placement of the lid with the positioning of the HOB output spout? I have one of them cube tanks (Fluval Flora) that has a glass lid flushed to the shape of the tank.