Datnioides are in their own family Datnioididae within the order Perciformes. Depending on the species, they max out between 12 and 24 inches. They are generally not aggressive to fish that are too large to swallow, with the exception of some occasional aggression between dats. Datnoids are best kept in groups of three or more to disperse any aggression and to keep solitary dats from getting too shy. There are five recognized species, three of which are generally considered FW species and the other two of which are FW and brackish:
FW/BW species:
New Guinea datnoid, New Guinea tiger (NGT)-- Datnioides campbelli (max size 16 inches)
Silver datnoid, American tiger (AT) -- Datnioides quadrifasciatus (max size 12 inches)
FW species:
Widebar datnoid, Siamese tiger (ST), Cambodian tiger (CT) -- Datnioides pulcher (max size 18+ inches, some say 24 inches)
Indonesian datnoid, Indonesian tiger (IT) -- Datnioides microlepis (max size 16 inches)
Thinbar datnoid, north Thailand tiger (NTT) -- Datnioides undecimradiatus (max size 16 inches)
I hope this helps. Dats rock!