[Peter Finke]

Stefanie, normally you don’t need a cover with Paros. In nature, they are fish living in greater depths than other anabantoids in flowing waters. Normally, you won’t therefore see them catching air; they never do this although their labyrinth is fully developed. You even could seclude the surface by a cover directly on the water surface, and the fish will live permanently in best health. You could never do this with any other anabantoid fish. They would drown within a few minutes.
And normally Paros don’t jump at all. This is quite different than with – say – Malpulutta kretseri; they are notourious jumpers, and other common anabantoids could be too. Paros are not, but: if they have no perfect conditions – water much too hard, pH much too high, many bacteria and germs in it – they come to the surface, catch air and – even may jump. Take as a rule: If fish jump that in nature don’t do that, it is because they feel somewhat uncomfortable. Something is wrong with the milieu you offered them If Paros find the right milieu, they don’t jump.
So I nevertheless recommend beginners to use a cover as Helene says: if you fill the tank nearly until its upper end. For you normally cannot provide best water conditions permanently. The structure of an aquarium is so different to a flowing rainforest stream that the germs will multiply although you try to prevent it. The plasticity of the fish’s organism will stand it nevertheless, and they will spawn and the young will grow, if things don’t get so bad than in the normal community tanks with fish fed by artificial dried food. Happily, we feed live food and Paros feed a little only. So things can’t get such bad. But it’s more difficult to keep their conditions in order than with “normal” ornamental fish.
I fill all my small 10-liter-tanks with water until a few millimeters from the upper end of the tank. They are all covered by a light plastic glass which is two millimeters thin, only. It’s very light indeed and unbreakable. You could buy it at “Obi” or another special market for home-workers. And it could be sewed or broken after having cut with a sharp knife. And you can bore or drill holes in it. It’s directly lying on the tank only two or three millimeters above the water surface. I have bored or drilled a ten millimeter hole in each of them very near to the front end so that I can feed the fish with a pipette through it without taking it away.
Paros are no fish for only keeping them for joy only; they don’t swin much around and in order to see their behaviour they must be bred.