Barbs don't form pairs.
When the fish are mature, take a nice plump female out and put her in a separate bare-bottom tank that is very densely planted (lots of java moss is good) and feed well with foods like bloodworms, shrimp etc.
When she looks nice and round with eggs, you can introduce a mature male. He should have a red band running along his sides.
Spawning (which barbs normally do in the morning) should commence not long after. The female will scatter her eggs in the plants and the male will fertilize them.
You need to then remove both fish or they will eat all the eggs. Hopefully, many will survive in the java moss before you get the pair out. The eggs should hatch in about a day and become free-swimming the next day. They can eat newly-hatched
brine shrimp, fry food, very finely crushed flakes etc.
You'll need to use a very fine siphon hose to remove leftover food and debris. A seasoned sponge filter should be used so fry wont' be sucked up.
Good luck! Odessa barbs are very pretty.
