[Peter Finke]

Daniel, everything Helene said is right. I only want to to supply some points.
1. The name of the location is Langgam (on Sumatra), not Laggam.
2. I am in doubt that the female you show to us is a phoenicurus (form of the tail fin, marking of the dorsal). But I can be wrong and it’s not important. Let them grow and display, then we shall see.
3. Your tank seems to be rather empty. Paros don’t live in their natural waters in the empty space but near or even in the riparian zones crowded with reed, near old twigs and branches of wood and masses of leaves that had fallen down. You should fill in some structures, best are small old pieces of dead wood from peat bogs. The usual aquarium plants mostly don’t stand the water values; small pieces of “Java moss” and “Java fern” could be helpful. Structuring the empty water will help the new fish to acclimate.
4. Small flocks of tiny barbs like Boraras spec. help also; they must be caught out if breeding begins.
5. Then at the latest you should remove that snails also, of which one is to be seen. They could not stand the normal water values because of missing Ca.
6. By the way: You don’t say anything on the water values. The pH must be fixed below 7.0, the calcium hardness around zero. The best is to measure electronically and try to get a Microsiemens more than 10 and less than about 60.
7. Your other fish are definitely no deissneri. P. deissneri is endemic on Bangka island and near to extinction. There is no commercial fishing. All places known for long to the specialists are definitely totally destroyed. We shall see later what you have really.
Best, Peter