HistoryGirl--nope--a 2 gallon tankis inadequate, and won't support their food needs.
However--the trigger is unlikley to bother a mandarin. Those bright colors indicate a thick, sticky slime coat that tastes awful--most predators leave them alone. I think mandarins are well suited for aggressive tanks that have enough live rock, simply because very few predatory fish compete for pods. I had my mandarin in with a picasso trigger, a volitan lion, and a snowflake eel with no problems. The mandarin and eel would hang out together, and the trigger and the lion completely ignored the mandarin.
However--the trigger is unlikley to bother a mandarin. Those bright colors indicate a thick, sticky slime coat that tastes awful--most predators leave them alone. I think mandarins are well suited for aggressive tanks that have enough live rock, simply because very few predatory fish compete for pods. I had my mandarin in with a picasso trigger, a volitan lion, and a snowflake eel with no problems. The mandarin and eel would hang out together, and the trigger and the lion completely ignored the mandarin.