Parosphromenus species have a fully developed labyrinth organ, but they don’t use or need it for normal life in floating waters with a rich oxygen content. If the milieu degenerates what whatever reason (and you can sometimes watch it in bad aquaria) they can use it and they do.
In your case it’s something different. As Deapin’ peat says your linkei male builds or renews a bubble nest. And here one must know that different species act in different a manner. P. linkei or P. filamentosus males in such situations frequently rise to the water surface and fetch air; their bubble nests are the biggest of all Paros.
With many other species you rarely become a witness of this; they do it at night or they do it much less than the named two. Many of their “bubble nests” are hardly existent, for instance ornaticauda or parvulus nests consist of the clutch only and nearly no bubble at all. Many other species (alfredi, tweedie, quindecim, pahuensis and most others) have very small bubble-nests that tend to diminish in the course of time; it’s a relic of a behaviour which is no longer needed.
So in your case it’s a typical behaviour of P. linkei or filamentosus (to a certain extent of the true deissneri and spec. Ampah, too) that belongs to his special way of building a relatively big bubble nest and his manner of renewing it eagerly during the first days of care for the eggs and larvae.