That is no tetra. Tetras have 4 unpaired fins (which is where they got their name from).
Take a look at Copella , also . Similar to Pyrrhulina but maybe not so common . Certainly NOT an Aphyosemion .
IIRC there's Copellas that aren't splash tetras , but your guess of P. brevis is probably as good as any of us are going to do .