NGT will beat the crap out of any tiger close to its size with the exception of thin bars
once NGT get to 8-10inch the turn crazy and don't tolerate any tigers
i have a 18 inch ST with a 5inch NGT no problems
i kept 1 x st and 1 x ngt in the same tank for ages they were best mates always shoaling together the 1 day the ST beat crap out of the NGT so bad i had to remove the NGT
when i put the NGT back into the tank he beat up 7 x 12inch ST nothing would mess with the NGT
don't underestimate the power and aggression of a NGT