The Blue Hippo Tang and 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 to see Dory the Blue Hippo Tang. 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 saltwater aquarium 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 Hippo 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?

Scientific NameParacanthurus hepatus
Common Name (Species)Blue Hippo Tang, Regal Tang, Blue Tang, Dory Fish, Pacific Blue Tang, Pacific Regal Blue Tang, Blue Tang Fish
OriginIndo Pacific
Care LevelModerate to Difficult
LifespanUp to 20 years
Tank LevelAll Areas
Minimum Tank Size120 Gallons
Temperature Range73 – 81 Degrees F
pH Range8.1 – 8.4
Filtration/Flow RateAll
Water TypeSaltwater
BreedingDifficult – tank bred available
CompatibilitySemi-Aggressive tanks
Ok, For Reef Tanks?Yes
Ok, For Inverts?Mostly Yes

The Dory Fish is known by various names including Blue Tang, Regal Tang, Blue Hippo 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. 

Finding Dory

They are recognized for their vibrant coloring, yellow tail, and bold black markings. 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 Hippo Tang is a very active fish. It 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 Hippo Tang) in an Aquarium

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

A Blue Hippo Tang (paracanthurus hepatus) 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 very large tank with lots of swimming room.  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 hippo tang. I have seen far too many local store happily sell a 1″ blue hippo 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.


The best example of a similar looking fish to a Dory or Blue Hippo 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 Hippo 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

If I have not scared you off in purchasing a regal 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 hippo 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 hippo 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 hippo 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 hippo 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

The blue hippo tang is an omnivorous saltwater 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 hippo 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 saltwater 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

A Blue Hippo Tang is a large saltwater fish that require quality water, filtration, and oxygenation. I would not recommend a hang-on back setup for tank with a Blue Hippo 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 reef 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.


Are They Aggressive?

Blue Hippo Tangs are considered semi-aggressive, which means they will be territorial and harass more timid fish. You can curb aggression with a larger tank. They are also aggressive to other tangs of the same sub-species. If you are considering multiple tangs, consider a tang of a different sub-species too maximize your chances of success.

What Do They Eat?

Blue Hippo Tangs are omnivornes, but do better with greens in their diets. A diet with greens like nori, spirulina, and algae are healthy for a blue tang. They will also eat meaty foods like mysis shrimp, brine shrimp, and black worms. A good frozen food to try is LRS Foods Herbivore Frenzy 

Are They Hardy?

They are not as hardy as other tangs can be. They are very susceptible to ich and other marine fish diseases. Tangs like the Scopas, Kole, and Tomini tang are better candidates for first time tang keepers.

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 :).


  1. Hello. Thank you for this information. I recently introduced a hippo tang into my tank. Tankmates are a scooter blenny, and a Banggai cardinalfish. I’ve noticed the hippo tang lays on top of my scooter blenny and follows ot around. Is this a sign of aggression?


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