Saltwater Aquarium/Unicorn tang


QUESTION: Hi David, I was at my local fish store to pick up a lawnmower blends for some green hairline algae, well the fish store sold me on a unicorn tang saying he will do better in my tank. So I bought him as he was a great price, he's about 3 inches so he's a juvvy anyways I got home and did some research and found out how big they get. Well I have a 55 gallon tank but it's a cube tank. (34 inches aross) so it's not to small but deff not big enough for the fish. My question is will I be able to keep him in the tank for a year or so and when he gets two big trade him in at the fish store? He's a beautiful fish and I would love to keep him if he will be Ok while his little. Thanks for all your help!

ANSWER: Hi Taylor:

Thank you for the question.

Your local fish store should have made you aware of the minimum tank size required for an adult Unicorn Tang, which is generally around 360 gallons...

With the proper care and pristine water conditions you should be able to keep your juvenile Unicorn Tang in your 55 gallon aquarium momentarily while it grows, provided there is space for him to swim freely back and forth in the aquarium. Unicorn Tangs are a schooling type fish, so they require open space to swim freely in the water column.

I wish you success with all of your saltwater aquarium endeavors.


---------- FOLLOW-UP ----------

QUESTION: Thank you for such a quick reply. I do have one more question after closely examining the tang I see what looks like a small clump of maybe 3 bumps on him. It doesn't appear to look like ich, and it's only in that one area. He is already eating and the LFS said they have had him for 2 weeks so he's not a fresh shipped fish. Should I be concerned of ich, as this is only in one spot? Thank you so much for your help!

Hi Taylor:

It's definitely something to keep a close eye on... unfortunately I couldn't say for certain would it could be. Contact your local fish store where you purchased your fish, and see if they have experienced what you're experiencing with your fish.


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David Ocreef


Technical saltwater coral reef related aquarium questions are welcome. Coral, invertebrate, and peaceful species of saltwater fish questions are welcome. Questions asked on Saturday and Sunday will be answered the following Monday. REMINDER: Please check the answers pool to see if your question has already been asked and answered. Questions typically are answered within a 48 hour period, however sometimes it may take longer.


I possess over twenty-five years of hands-on experience and knowledge in the ecology of aquariums. Beyond the traditional, I have successfully tested and sustained environments that have been uncharted territories for hobbyists, for decades. I am the first to admit I don't know it all because there will always be something new, amazing, and exciting to learn about, as discoveries are made. It's a hobby one can never outgrow, or grow tired of.

MASNA - Marine Aquarium Society of North America. Director of Orange County Reef Aquatics -

Publications,, and many others.

After High School, my experience and love of marine animals influenced me to take up studies in Marine Biology. Throughout college, I studied Microbiology with an emphasis on Marine Life, as well as numerous other sciences. I continued to advance in this hobby, by building a dozen or more saltwater ecosystems all utilizing Microbes as the major source of my filtration method.

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