Some General
Information
Common Name: Walking Catfish
Scientific Name: Clarias batrachus
Distribution: India, Sri Lanka, Southeast Asia;
introduced in USA: Florida
Diet: Seriously I think they eat anything. They are scavangers and
eat fish, fish waste, fish food etc etc
Temperament: From what I've seen, they tend to
hide alot when young, and they do squabble amongst themselves. Tend
to hide when large as well though it doesn't take kindly being
bullied and bites back (Experience when kept with a Flower
Horn)
Tankmates: Anything as long as it can't eat
it.
Color: Usually grey but there are albino ones or
the 'rarer' ones with markings.
Other Comments: The walking catfish is, indeed,
capable of moving on land and, when it does so, is able to breathe
air. It belongs to the family Clariidae, whose members have
additional, specialized breathing organs opening off the gill
arches. These are saclike structures containing many-branched
extensions, well supplied with blood vessels for respiration.
An elongate fish, this catfish has long-based dorsal and anal fins
and several pairs of sensory barbels; its skin is scaleless but
liberally supplied with mucus, which protects the fish when it is
out of water. These catfishes live in ponds or temporary pools,
some of which may disappear in prolonged dry spells. When this
happens, the catfish can move overland to another body of water,
making snakelike movements and using its pectoral fins as "legs."
If necessary, the walking catfish can bury itself in mud at the
bottom of a pond and remain dormant throughout a dry season until
the rains return.
People do keep them as an oddity in the west as pets but over here
it's very commonly sold in our local aquariums as feeder fish. My
rays love to eat them. I've also noticed that they are considered
intelligent fish.
As you know, rays are bottom feeders so instead at the bottom like
they usually do, the walking catfish stays at the top now, hiding
at the sides. However, the rays started going up to eat them now
and the walking catfishes now stay in the middle of the tank, right
at the top where the rays find it hard to reach them.
Species
Stats
Temperature: Tropical.
Water: I don't think they are fussy about water.
They can live in water filled with turtle piss too 
pH: 7.0 ...but seriously I don't think it matters
too much
Max Size: Around 50cm
Information & Pictures taken from:
http://mbgnet.mobot.org/fresh/wetlands/animals/catfish.html
http://www.aquahobby.com/gallery/gclarias.html
http://www.scotcat.com/factsheets/clarias_batrachus.htm
and own experience 
