Finding Dory – What You Need to Know About A Blue Tang in a Saltwater Aquarium

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I am sure you have have all heard of Pixar’s new movie “Finding Dory” coming out this month. I am actually really excited myself having a young child to bring to the movie for the first time. I really enjoyed the original movie “Finding Nemo” when it came out in 2013.

I also remember working at a local fish store during this time and the demand surge for clownfish. I remember the excited parents coming into the store wanting to get a clownfish for their tank and not really knowing anything about care for the cute little orange fish they wanted. I know many experienced hobbyists cringe at the thought of having someone completely unknowledgeable trying to purchase these fish, but I always saw this as a learning opportunity.  The hobby has changed dramatically over the years and these customers are a blank slate lacking the thousands of opinions from hard-core forums.  I see these experiences as opportunities to welcome new people into the hobby. It is also a huge plus when parents have the opportunity to share the wonderful learning experiences with children about not only the ocean world, but about the technology and craft behind the hobby as well. There are so many opportunities to teach children – biological, chemistry, trade skills from DIY projects, plumbing, software, etc. I’m going a little bit off topic in my excitement though – I promise you I will follow up in a later post about the benefits and activities you can work on with your family when you have an aquarium.  

As a responsible aquarist, I seek again to provide this learning opportunity to parents and children about the “Dory Fish” AKA Blue Tang.  With the new Finding Dory movie coming out, there will be a large demand to have this fish in home aquariums and there is a whole lot more to educate new comers into the hobby about Dory.  I will be focusing on the following in this blog post:

  • What is The Dory Fish
  • Realistic Expectations Regarding the Dory Fish
  • Alternative similiar looking fish
  • Selection and Introduction
  • Nutritional requirements
  • Care requirements

So What Is A Dory Fish?

Finding Dory

The Dory Fish is known by various names including Blue Tang, Regal Tang, Blue Surgeonfish, Indo-Pacific Blue Tang or by its scientific name Paracanthurus hepatus. These tangs are found in the Indo-Pacific from East Africa to Japan and swim at depths of 30 to 130 feet.  

The terms Tang and Suregonfish actually refer to the extremely sharp spines on each side of the fish’s tail, which are said to resemble surgeon’s scalpels. These spines remain flat against the fish’s body and extend only when they are threatened or alarmed. 

They are recognized for their vibrant coloring and yellow tail. They are capable of adjusting their color intensity of their hue from light blue to deep purple. These colors will often fad as the fish ages. 

Adults average about 12 inches in length and can be found living alone, in pairs, or in schools of 10-12. They are known to live as long as 30 years in the wild – which is longer than any cat or dog! Blue tangs will easily swim miles a day in the ocean looking for food and may move seasonally. They feed on algae and use their sharp teeth to rip algae off rocks and corals. Their diet is not only important for the tang fish itself, but also for the health of reefs as they prevent algae from overgrowing and suffocating corals. 

Realistic Expectations of a Dory Fish (Blue Tang) in an Aquarium

So we have learned that a blue tang can grow to a foot long, can outlive your cat or dog, and swim miles every day. What does that mean in the aquarium? After all, you likely have seen small 1 inch blue tangs for sale at your local fish or chain store. Please do not let this fool you. A small 1 inch blue tang will quickly outgrow a small aquarium and needs a needs a proper tank tank size for a long and healthy life.

Dory needs a proper tank with plenty of space to move around because as we all know Dory just loves to keep swimming. So what does proper tank mean? Well, I’m going to be very honest with you. Dory is a large fish and therefore requires a large tank.  So this means the following:

  • Minimum tank length – 60 inches
  • Minimum tank volume – 120 gallons
  • Recommended tank length – 72 inches
  • Recommended tank volume – 180 gallons

I know these recommendations are going to be outside of many people’s budgets or wants in the home, but I would rather be honest and realistic about the requirements about the blue tang. I have seen far too many local store happily sell a 1″ blue tang to a new hobbyist with a small tank without thinking twice about the care and requirements.  I’m all about responsible aquarium keeping and want to ensure you are successful for the long-term.

Even Petco is starting to get on-board with notices about Dory care

If getting a large tank is something not feasible for you, but you still want a Dory you are still in good shape because there are fish are would make an excellent alternative.

Alternatives to a Dory Fish (Blue Tang)

The best example of a similar looking fish to a Dory or Blue Tang are yellow-tail damsels. I have been in the aquarium industry for many years and you would be surprised how often I would hear “Look – a baby Dory!” – from a child pointing at the yellow-tail damsel in a tank. In fact, my story was so interesting that I was actually interviewed by the Huffington Post about my experience with the Blue Tang and the yellow-tail damsel.  

Yellow Tail Damsel

Not only is the yellow-tail damsel much smaller than the blue tang, but it is also very hardy. In fact, many damsels from the Chysipetra genus would make good alternative with their vibrate blue and yellow colors. I actually wrote a blog post earlier about them that you can read about here

There are also some fish among Nemo’s group of friends from the first movie that would make good additions to a saltwater aquarium – including the Gurgle the Royal Gamma and Nemo himself that I wrote about earlier in my Top 10 Saltwater Fish List. Even if you are going to get your own Dory, these fish make perfect tank-mates for them.

Selection and Introduction of a Dory Fish (Blue Tang)

If I have not scared you off in purchasing a blue tang, then I take it you know full well the requirements of keeping this fish so I will continue on. When selecting a blue tang, it is best to purchase a tang at least 3 inches, not thin, actively feeding, and shows no physical signs of disease. The truth with the blue tang is they are highly susceptible to parasites like ich and marine velvet as well as head and lateral line disease. I have seen far too many tank crashes where a blue tang is added, they get ich, then the tank quickly crashes as the disease spreads.  Because of this, it is highly recommended that you quarantine a blue tang before introducing them to your display tank. The quarantine period will help ensure that your fish is healthy before introducing them to your main tank. Outside of proper selection and quarantine, the main reason why these fish often get sick is lack of space (which I covered earlier) – and lack of nutrition.

Nutritional Requirements of a Dory Fish (Blue Tang)

The blue tang is an omnivorous fish and providing them with a solid mix of meaty and green based foods is absolutely critical in keeping your tang healthy and happy. Seaweed probably the best green source you can feed your tang. One of the biggest secrets out there if you can get your tang to eat it is actually Nori sheets from your grocery store. They are way cheaper than the seaweed products that sellers like myself can get and you can pick them up locally.  Please ensure that seaweed is the only ingredient and no salt is added. Romaine lettuce and spinach work as well, but there is some debate about this from purists in the reefing community that feel that greens of a marine origin are best. They also are not as nutritious as seaweed. 

A feeding clip is incredible handy for feeding Tangs. These clips allow the blue tang to naturally graze and keeps the seaweed from spreading around your tank. It may take some time for them to get used to eating this way, but once they get used to the clip it will be a feeding frenzy every time! Here is an example of a Palting from the ReefCentral forum feeding his tangs Nori from the grocery store: 

For meaty foods, I would recommend LRS Foods. LRS foods are one of the finest fish foods in the world, used by top breeders in Europe and North America. You want to get top quality food for a blue tang as nutrition is such a critical aspect from keeping them disease food.

Care Requirements of a Dory Fish (Blue Tang)

Blue tangs are large fish that require quality water, filtration, and oxygenation. I would not recommend a hang-on back setup for tank with a Blue Tang. You absolutely have to go with a sump setup and quality protein skimmer and/or algae turf scrubber. The sump will provide you with additional tank volume, stability, and utility for added equipment like auto top offs and controllers which you will likely want to invest in order to ensure your aquarium is as stable as possible. Blue tangs live in environments with natural strong flow and lots or rocks so the flow and aquascaping of a mixed reef tank definitely suits them.

They are generally compatible with most other aquarium fish, but be very careful with keeping more than one. Two blue tangs in a single tank will often show aggression except in very large tanks. They are also known for getting aggressive in smaller tanks, which is another reason I recommended a tank volume size of 180 gallons.

If you looking for your very own Dory – We are here to help you!

I have gone over what is a Dory fish, recommended tank size, introduction, nutrition, care, and even alternative fish. Following these guidelines and tips in this post will help you succeed in keeping your very own Dory (or “baby dory”). If you have any additional questions, leave me a comment below. Myself and the team here are Aquarium Store Depot are happy to help! See you next time :).

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