They would make a great addition to your tigrinus's diet, throw in a school of rummy nose too for dessert. All kidding aside, if it fits in his mouth, he will eat it eventually. That's not to saw you shouldn't do it. A guy I knew once loved jellybean parrots. Not nearly as much as his arowana though. After a while it was all he would eat. Expensive diet but one of the best looking aros I have ever seen.
Try an arowana, peacock bass, or stingray. I have all 3 with my tig and they get along great. Started all about the same size a year ago, now tig is 15 inches not counting trailers, rays are a foot in diameter, and aro is about 20 inches.
It depends on the Tigrinus. I have a 17" Tigrinus, lives with 2-3" Dats, 6"-9" Clown Loaches. Never fed it live food, only eats massivore. You must be going for the cool schooling, colorful effect with the Roselines, I have thought of it as well. But for $14 a pop, do a trial run with a group of neon tetras. Just my opinion.
if its four inches it would probably work temporarily. Roselines on long island go for a lot more than 6 bucks. The cheapest ive evr seen them being sold was 25 and the average is 40
I still think it would try to eat them. Expensive feeders, they have a slender body type, at least go for something with a more robust body type of fish if u want tankmates.