Of course, we should always think of the potential damage the aquarist hobby is responsible for. But as far as we know this in not one of the Parosphromenus problems.
Nearly all Parosphromenus in the zoo-trade are wild-caught animals. Nobody in Asia breeds the “difficult” fish of the blackwaters. Catching them is a work for poor people in the country. But they don’t catch in all seasons. It would be much too hard and troublesome. They concentrate on the after-breeding season when the waters abound with young. Of course, Parosphromenus are difficult to be caught even then (because they hide in the riparian grasses and the layers of leaves on the ground and don’t swim in the free water, but when the young have grown to half an inch or a bit more many are to be caught in waters which at other times of the year seem to be empty of them.
We have never heared of this deadly damaging a population; it would be much too hard to catch to that extent. The deadly dangers of Parosphromenus lie in the destruction of the rainforest and the exploitation of the peat soils by that palm-oil-plantations (and to a minor extent by chemical immissions and the construction of streets and settlements).
Every year thousands of young Parosphromenus of quite a few species are caught this way and some hundreds die in Asia already mostly short after having been caught and not properly cared for with fresh water. Many hundreds are shipped to other continents in more or less bad condition. Once a German wholesaler phoned us that he had just received 800 ornaticauda (a difficult species) and half of them were dead at that moment or nearly dead already.) We could save about 80 of them burt most died after two or three weeks because of the stress they had to endure.
Mostly, the commercial trade concentrates on large populations (as that of spec. Sentang or spec. “Blue line” on Sumatra). Most other species are uninteresting commercially. It’s a speciality if you get opallios or filamentosus, and you never get deissneri or allani.
There is only one way out for the aquarists, and that is breeding, breeding, breeding, and the distriution of the young to as many friends as possible. Each Paro-friend should breed his fish. Self-bred fish are more healthy than all that have been experienced the commercial martyrium.