As far as rare butterflyfish go, the French Butterfly (Prognathodes guyanensis) is arguably one of the rarest and most expensive. This deepwater gem, like many others showing up in the hobby as of late, is a Caribbean native that is typically found at depths greater than 100m (330ft) and is generally inaccessible to most collectors. Because of this, this butterfly species is rarely seen in the aquarium trade, and when it does make an appearance, individuals are quickly snapped up by fish keepers in Japan. Occasionally, one individual here or there slips buy the ever watchful eye of overseas aquarium keepers and makes it to the US. Unfortunately, the rare beauty shown above falls into the first category. Shown off by the guys at B-Box Aquarium, the sizable butterfly appears healthy and can be seen picking at the rocks inside its temporary housing, which are both good signs considering the fish’s finicky nature. To give you a good gauge on the butterfly’s rarity, the expected retail price on this fish should be around $1500-2000.