Black-backed butterfly fish: they are dull colored, most have patterns with striking backgrounds of blue, red, orange, or yellow. Many have dark bands across their eyes and round, eye like dots on their flanks to confuse predators as to which end to strike and in which direction they're likely to flee.
Hippocampus seahorse: they have a upright position, horse like head set at right angles to the body make it resemble a knight in a chess set. They have a tail which it uses to hold onto seaweed and coral. They are used for aquarium trade.
The Great Barrier Reef is the ideal ecosystem for both hippocampus sea horses and blackback butterfly fish because they both have to be in tropical waters and there both found in pacific waters which is where the Great Barrier Reef is located