Atlantic Blue Tang, Acanthurus coeruleus. Atlantic Blue tang are usually bright yellow until they reach about 2 inches, after which they will begin to turn blue. There are exceptions to this, and occasionally we see 5″ yellow phases and 1″ blue phases, but for the most part they are yellow when they’re small and blue when they’re big..
Atlantic tangs and surgeonfish are primarily herbivorous at all stages of their life, and are an important component in algae control on the reefs of Florida and the Caribbean. In the wild they can survive on just algae because they eat a wide variety of algae and the algae have all kinds of epiphytes growing on them, so they get plant and animal proteins (and fats) with every bite. In a home reef tank there is not a wide variety of algae and not nearly as many epiphytes, so I recommend that you to feed them regularly with some sort of prepared pellet food so that they are not totally dependant on the algae in your system.
Tangs will do a good job keeping algae under control in your reef tank, but I doubt that they can do the job alone, so you should consider including some invertebrates such as herbivorous snails or blue legs to help out.
Tangs are also very susceptible to Ich, so be sure to quarantine them for two weeks prior to adding them to your main tank.
Small: 1 to 2 inches
Medium: >2 to 3 inches
Large: >3 to 5 inches
XL: 5+ inches
Please Note: Any new fish purchased from us or from a local pet store should to be quarantined. All fish from anywhere in the wild can be possible carriers of bacteria and protozoa that can lead to an infection in your system, so we always recommend that you use some sort of quarantine system prior to adding them to your system. If you have a fish only system and can medicate the whole system, you may not need a separate quarantine tank. If you have a reef system that cannot be medicated, a good ultraviolet sterilization system should prevent any kind of disease outbreak. We medicate our system for bacterial infections and protozoans, but because we dont always hold our fish for long periods of time, there is no way to be sure all the protozoan cysts have been killed. A little bit of prevention will save you lots of trouble down the line.