Hate to say it but I don't follow that since I have a male and a female and both have the black fins on the bottom and the black dot has blue sheen on both of them the pink belly I found it the only 100% way to tell if some are female but yours looks like a male since his dorsal fin has one...
Mine don't school at night but any other time they are close together well except when I first got them where they were 3 shoals of 4 or in pairs but that was the first week
Seeing as how all my fish tend to find the bloodworms which are red very easily or the red flakes I use from time to time I don't think a red net would help to much I might do it if it matched my tank but other then that I would probably just stick to a normal black net
Sorry haven't been on the forums for a little while and yes pink bellies are 100% female as for males that is another story I found looking at the dorsal fin and looking for a larger spike is the best way but that is just me
As for them going with gourami there might be a little fighting since...