Blue Hippo or Regal Tang

Paracanthurus hepatus

This is a popular and stunning marine fish that goes by many names; it is AKA as the Pacific blue tang, the regal tang, the palette tang, the flag-tail tang, and the hippo tang (probably the most common name used today, though I have no idea why because they don't look much like hippos to me :-).

While I am not a member of the "tang police", after trying to keep one in my 60gal tank for a year, I do see what they mean. I felt so bad for him that I finally sold him to someone with a bigger tank. Tangs in Nature are not true reef-dwelling fish, in that they don't only keep to a small territory; they are open water schooling fish that are breef visitors to the reef. You can tell by their very shape (streamlined and narrow) that they are built for speed, and need the room to swim. Some people would say that the limit for even the smallest tangs is 75 gallons, with larger ones needing 90-100 gallons and up.

To me, the actual cut-off between "ok" and "poor" is debatable still, but I do agree that they need room. When they feel cramped and stressed, they are very ich-prone. In marine reef tanks, SW ich is best controlled by a combination of feeding crushed garlic (contains an antiparasitic compound called allicin that helps the immune system) and use of cleaner animals like the cleaner shrimp. To keep them healthy, they also need to be fed frequent supplements of herbivorous foods like nori and veggies; they will eat algae off of rocks and readily take all sorts of prepared foods, but require a diet high in vegetable matter.

Keeping tangs together in the same tank is not easy if they are not raised together. Usually, similarly shaped tangs will fight; they have a sharp blade on their tails (one reason why tangs are also called "surgeonfish" as a group) that they can viciously slash their opponents with, sometimes killing them. They do this because like so many reef fish, their natural instinct is to defend territory. Usually the loser will be the new tang, encroaching on the established tang's territory. But this is all very unpredictable, because every tang is different.

If you should wish to introduce a second tang at a later time, the best idea is to get one of a totally different shape. As always, it is hard to predict for sure if they will get along, but this lowers the chances of them fighting. It also helps to have a large enough tank so they can establish territories of their own and stay in that region; for multiple tangs, this usually means a tank greater than 100 gallons.