Welcome to the forum
To sex tiger barbs you need to look at the dorsal fin (that's the one on their back); if it's mostly red, the fish is male, if it's only pale red or clear, the fish is female; that should hold true, even though your fish are strangely coloured. In this case, the fish in the top picture is male, the other, female.
Tetras are much harder to sex. You might be able spot the females, if they were full of eggs, as you'd see them looking fatter than the males, especially if viewed from above, but there's no way of sexing that one, from that picture.
I know this is not directly related to your question, but your fish don't look like proper glofish to me, they look dyed
This means they've been injected with a dye that will fade in time, but it's a very stressful process for them (many die during it) and it could affect their long term health.
Are these they only fish you have? Both tiger barbs and widow tetras can be very aggressive, and need to be kept in large shoals, if that aggression isn't to become a problem, so that's something you might need to watch out for
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