  The electromagnetic string fluid (EMSF) is an anisotropic charged string
fluid interacting with a strong magnetic field. In this fluid we consider the
double congruence defined by the 4-velocity of the fluid $u^a$ and the unit
vector $n^a$ along the magnetic field. Using the standard 1+3 decomposition
defined by the vector $u^a$ and the 1+1+2 decomposition defined by the double
congruence ${u^a,n^a}$ we determine the kinematic and the dynamic quantities of
an EM string fluid in both decompositions. In order to solve the resulting
field equations we consider simplifying assumptions in the form of
collineations. We decompose the generic quantity $L_{X}g_{ab}$ in a trace
$\psi$ and and a traceless part $H_{ab}$. Because all collineations are
expressible in terms of the quantity $L_{X}g_{ab}$ it is possible to compute
the Lie derivative of all tensors defined by the metric i.e. the Ricci tensor,
the Weyl tensor etc. This makes possible the effects of any assumed
collineation on the gravitational field equations. This is done as follows.
Using relevant identities of Differential Geometry we express the quantity
$L_{X}R_{ab}$ where $R_{ab}$ is the Ricci tensor in terms of the two
irreducible parts $\psi,H_{ab}$. Subsequently using the gravitational field
equations we compute the same quantity $L_{X}R_{ab}$ in terms of the Lie
derivative of the dynamic variables. We equate the two results and find the
field equations in the form $L_{X}{\text{Dynamic
variable}}=F(\psi,H_{ab},{\text{ dynamic variables}})$. This result is general
and holds for all gravitational systems and in particular for the EMSF.
Subsequently we specialize our study at two levels. We consider the case of a
Conformal Killing Vector (CKV) parallel to $u^a$ and a CKV parallel to $n^a$.
