Kleini Butterfly (Chaetodon Kleinii)

Also Known As: Sunburst Butterflyfish, Brown Butterflyfish

Compatibility and Behavior
The Kleini is the butterfly for people who've heard butterflies are difficult. It's widely regarded as one of the hardier, more adaptable members of the family, which makes it a sensible entry point into a group that has a reputation for being finicky. The look is on the natural, understated side: a warm golden-brown body with darker patterning across the flanks and a classic butterfly profile, the coloration deepening and the contrast sharpening as the fish matures. Between the rounded shape, upright dorsal, and steady gliding swim, it carries a calm but confident presence as it cruises open water and works the rockwork for food. Temperament tends toward peaceful with dissimilar tankmates, and it mixes well with calm tangs, wrasses, and Anthias when introduced thoughtfully, though it may get mildly territorial with other butterflies or similarly shaped fish in smaller tanks or when added after everyone else is established. As with the family generally, it's reef safe with caution: while foraging it may nip soft corals, LPS, zoanthids, and clam mantles, so it's usually a better fit for a FOWLR or a very carefully planned mixed reef.

Aquarium Requirements
Give this one a mature tank with plenty of live rock, open swimming room, and stable water quality. Small individuals around 1.5 to 2 inches make a practical start in a 75 to 90 gallon tank, while medium fish are better kept in 100-plus gallon systems with a long footprint and strong filtration. Provide moderate, well-oxygenated flow and a layout that balances open water with rocky grazing areas and sheltered retreats. Diet is your best tool for easing pressure on corals: a varied menu of mysis, finely chopped seafood, quality marine pellets, and frozen omnivore blends keeps the fish in good condition and takes some of the edge off its interest in sessile inverts.

Specifications
Approximate Size: Sm: 1.5–2", Md: 2.5–3"
Diet: Omnivore; mysis, chopped seafood, plus quality marine pellets and frozen blends
Origin: Indo-Pacific
Care Level: Intermediate
Reef Safe: With caution
Temperament: Peaceful to semi-aggressive
Minimum Tank Size: 75 gallons for small specimens, with a larger system required as it grows
Special Considerations: Reef safe with caution, as it may nip soft corals, LPS, zoanthids, and clam mantles, so best in a FOWLR or coral-cautious setup; one of the hardier/beginner butterflyfish, though still best with some butterflyfish experience; can be territorial toward other butterflyfish and similarly shaped fish