hi guys..... back here in the Philippines we call it SDS (Sudden Death Syndrome)...
some guys here reported that there NTT's where feeding well, healthy and all then all of a sudden it just dashed all around the tank then float! some like what other guys here mentioned heavy breathing and always at the side which i think is gill flukes....
NTT i guess is the least hardy of the datnoid species. thats why here we prefer to get NTT that are atleast 4-5" already to minimize the SDS. we avoid buying NTT smaller than 4" because they are more prone to this...
$200 is abit too high for NTT... here in our place it cost around Php1,500-2,000 ($1-Php.48) $38-$42 for 4-5". for $200 you can buy a bigger NTT atleast 10" big