8 Saltwater Fish Beginners Should Avoid

8 Saltwater Fish NOT For beginners

If you are a beginner in the saltwater aquarium hobby, you are most likely dreaming of having a tank set up with some amazing colorful fish and corals. I think we all dream of that and while it is definitely possible to have, you must take precautions when choosing the proper fish for your tank. Not all fish are suitable, and some have special needs and could be a concern for other tank inhabitants. As a beginner, choosing the wrong saltwater fish can be costly and frustrating when things don’t work out as planned. In this article, I will show you 8 saltwater fish that beginners should avoid.

  • Green Mandarin
  • Powder Blue Tang
  • Six Line Wrasse
  • Damsels
  • Copperband Butterfly
  • Anthias
  • Lionfish
  • Picasso Triggerfish

1. Green Mandarin Dragonet

Green Mandarin (Synchiropus splendidus)

In my experience with the Green Mandarin, they are one of the most difficult fish to keep even for the most seasoned hobbyist. So if you are a beginner with a new tank, you should avoid these fish.

The Green Mandarin is a beautiful fish with stunning colors. They are one of those fish that everyone wants but shouldn’t have unless your tank is very well established and healthy. They are a peaceful fish that won’t do well in a tank with any others that are aggressive.

The mandarin is also slow to compete for food and unfortunately is known to starve to death due to malnutrition. They require a large supply of copepods, amphipods to survive which new saltwater tanks don’t have. Some people who have mandarins will also incorporate a refugium to grow copepods for them to eat. So unless you have a well-established saltwater aquarium with an unlimited supply of copepods, you should avoid the Green Mandarin.

2. Powder Blue Tang

Powder Blue Tang

If you want to have a Powder Blue tang in your aquarium, you will need to plan everything else around it. These fish have a few main problems that you need to know. First, they require a large tank. Powder Blue tangs can grow to be quite large, so a big tank is required which beginner hobbyists don’t generally set up for their first tank. Second, they are susceptible to attracting a disease known as white spot disease or ich. It is very common for them to get sick and for that reason, many people decide not to keep them. Third, they are very picky eaters and will sometimes go long periods without eating anything. They are not recommended for beginners.

3. Six Line Wrasse

Six line wrasse

The Six Line wrasse is a very active fish that is fun to watch. They are also very colorful and hardy. Sounds like a great fish to have, right? Not so much.  The problems with the Six Line wrasse start right away when you first get it. They sometimes don’t acclimate very well to a new tank and take a while to settle in. For the first few weeks to a couple of months, they may seem fine in your tank, and then one day they can snap and start bullying and taking out other fish in your tank. They become very territorial and will not tolerate any other tank inhabitants. This 1 fish can cause a huge amount of problems and should be avoided for beginners.

4. Damsels


Many Damselfish are commonly found in saltwater tanks. They are very hardy, active and inexpensive to purchase. Some hobbyists will use damsels as the first fish put in the tank when cycling a new tank. I don’t agree with this as it is unfair to the fish, but many people do it. The problem with Damselfish is that they are very territorial and aggressive. They are known for bullying other tankmates and can also attack and bite you if your hand is in the tank. With an established tank and proper tankmates, certain Damsels can be a nice fish to have. For example, the yellowtail damsels seem to be not aggressive. But for the most part, they are just a huge nuisance.

5. Copperband Butterfly

The Copperband Butterfly is another fish that requires a well-established, mature tank to thrive and stay healthy. They are considered reef safe with caution and can pick at corals. These fish are very sensitive to bullying and can often jump out of the tank if you don’t have it covered. They are difficult to feed and require worms, bugs and other microorganisms to feed off of which form on the live rocks. They will also eat aptasia, which is another common issue many new beginners have. The Copperband Butterfly is commonly available and is reasonably priced, but are not recommended for beginner tanks.

6. Anthias

Lyretail Anthias

Anthias fish is one of my favorite fish in the hobby. There are a few varieties commonly available, including the Lyretail. There is no doubt that these fish can be some of the most colorful fish in the hobby. They are also fun and very enjoyable to watch. But they are not recommended for beginners. Here’s why.

First, the Anthias requires a larger tank. They don’t grow to be a large fish, but they need plenty of open swimming space as they are constantly moving. They prefer a strong current in the tank, so a proper wavemaker is a must. They also need to be kept in groups. You can’t have just 1 or 2 in your tank. They are a schooling type fish and usually are kept in groups of 1 male and 6 females. In order to avoid aggression, there must be only 1 male. The cool thing about Anthias, is they are hermaphrodites meaning they can change sex at will.

The biggest concern with keeping Anthias is the feeding requirements. They must be fed several times per day, as they constantly need to eat. Feeding them once a day with some flakes or pellets is not an option. Most hobbyists will fail at keeping Anthias due to the important feeding schedule. A solid option for Anthias food is live copepods. You can buy bottles of these online or at your local fish store, and it is a great food option for them.

7. Lionfish

Close-up Photography of Brown and Beige Lion Fish

Lionfish are a unique predator fish that will definitely draw attention to your tank. These fish are very aggressive and can be the only tank inhabitant. Nothing else will survive in the tank. Anything that will fit in their mouth will end up there. Snails, crabs, shrimp and any other fish will become food for a lionfish. If you have a dedicated tank just for 1 Lionfish, they can be very entertaining and fun to keep. You can use a long feeder to provide many frozen foods, including shrimp; they will gladly take it once they get used to you feeding it. But be careful: I should mention that they are venomous and can sting you! This can cause severe pain, swelling, and blistering that requires medical attention. Clearly these fish are not for beginners.

8. Picasso Triggerfish

Picasso Triggerfish

The Picasso Triggerfish is one of those fish that every saltwater hobbyist would love to have. They have amazing colors, are very active and can truly be a centerpiece fish of a large aquarium. Large being the important word.

These fish can grow to be very big and should only be kept in tanks of 200 gallons or more. They are also aggressive and will generally only tolerate other tankmates that are larger and have plenty of swimming space. It’s common for Triggerfish to knock over rocks and other decorations in the tank. This could be disastrous if you don’t plan the proper aquascape.

Also, the Picasso can be very picky eaters. It’s important to feed them a few times per day a variety of frozen fish foods that they will accept. They are not reef safe and will eat invertebrates. So they will need a large tank by themselves or with other large aggressive fish, no corals, and no cleanup crew. This is one fish that is not meant for beginners.

So as you can see, not all fish are for beginners. If you are setting up a saltwater tank for the first time, you need to do your research to prevent a costly mistake and frustration!

Thanks for reading!

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