Are they the same plants

I grew quinoa this year which has a good quality protein seed also. I grew 2 varieties from real seeds. Temuco variety gave the highest yield: 1.2kg. I got 1.7kg from about 30 plants of the 2 varieties in total . I did get some Amaranth seeds a few years ago but never tried it as it looked a lot smaller than quinoa and that was small enough.
When I harvested it, there had been some thieving by birds even though the seeds are coated with saponin which is supposed to deter them. This needs to be washed off before using which isn't the case with amaranth.