teacup rays if thats what you want to call them do fine with tigrinus
if you are asking if they will be ok with RTC then your tank must be MASSIVE to home a RTC
retic are no harder to take care of than any other rays its just they come into LFS at a very small size and in very bad condition and most times they are skinny and not feeding if you get them feeding they normally do fine
the 1st rays i had were 3 retics and it was before the internet so not much info to hand i done 1 very small water change per month with very bad filtration and they did fine for 2 years when i sold them and moved up a step to leo