I think those things might take over the surface. Looks like they require more of a pond or cold water biotope. Seems they need "pond" type micro-critters to eat. They are to small to eat your fish, even the neons. The barbs however may take care of the neons anyway. If not the guppy's. Barbs are semi-aggressive. Not a good mix with tetras, guppy's and whatever the pink striped thing might be, may be in danger.

The pink and yellow fish is probably a "painted" glass fish. These guys are injected with dye. The dye doesn't last long and the fish tend to be sickly for life because the process is so stressful.

Adrea