  Cluster faint low surface brightness galaxies (fLSBs) are difficult to
observe. Consequently, their origin, physical properties and number density are
not well known. After a first search for fLSBs in the highly substructured Coma
cluster, we present here a search for fLSBs in Abell 496. This cluster appears
to be much more relaxed than Coma, but is embedded in a large scale filament of
galaxies. Our aim is to compare the properties of fLSBs in these two very
different clusters, to search for environmental effects. Based on deep
CFHT/Megacam images in the u*, g', r' and i' bands, we selected galaxies with
r'>21 and surface brightness > 24 mag/arcsec-2. We estimated photometric
redshifts for all these galaxies and kept the 142 fLSBs with photo-z<0.2. In a
g'-i' versus i' color-magnitude diagram, we find that a large part of these
fLSBs follow the red sequence (RS) of brighter galaxies. The fLSBs within
+-1sigma of the RS show a homogeneous spatial distribution, while those above
the RS appear to be concentrated along the large scale filament of galaxies.
These properties are interpreted as agreeing with the idea that RS fLSBs are
formed in groups prior to cluster assembly. The formation of red fLSBs could be
related to infalling galaxies.
