  We explicitly construct the four and two fermion zero modes for the
mixed-flux generalization of the Hofman-Maldacena giant magnon on two of the
AdS$_3$ backgrounds with maximal amount of supersymmetry, AdS$_3 \times$S$^3
\times$T$^4$ and AdS$_3 \times$S$^3 \times$S$^3 \times$S$^1$. We also show how
to get the $\mathfrak{psu}(1|1)^4$ and $\mathfrak{su}(1|1)^2$ superalgebras
from the semiclassically quantized fermion zero modes.
