a blue and yellow Damselfish swimming alone

Looking for a pet to keep your children entertained? A Damselfish might be the perfect solution. Damselfish are small, colorful fish that are native to tropical waters. They are usually found in coral reefs, and are very active and curious. The gentle, colorful fish are very entertaining, but they’re also quite easy to care for, even for the most inexperienced aquarist.

Damselfish aren’t as flashy as clown fish; they don’t have big horns or elaborate patterns. They aren’t particularly big, and they tend to stay in the background. 

These little fish are a popular choice for many saltwater fish keepers because of their adaptability, their hardiness in captivity, and their tiny size. As a family pet, a damselfish is ideal for someone who wants a pet that is easy to care for and that won’t require a lot of attention.

Most people confuse the Damselfish with Cichlids because they look quite similar. Their colors are also amazing, but different from the colors and patterns that Damselfish have.

These tropical fish are hardy, fun for children, don’t grow too large and are relatively easy to care for. Though they’re typically kept in tanks with only other damselfish, they can be kept in a peaceful community tank with other small, non-aggressive fish, as long as they are given plenty of space to avoid being eaten.

Damselfish Information

  • Average size: 2 to 7 inches depending on variety
  • Colors: Red, Yellow, Blue
  • Good Pet: Yes
  • Tolerance to Heat and Cold: Yes
  • Good with Other Damselfish: Yes
  • Good with Other fish species: Moderate
  • Good for Less Experienced Pet Owners: Yes
  • Attention Needs: Low
  • Health Concerns: Marine Ich and Fin rot
  • Average Life Span: 5 to 6 years

Physical Appearance of Damselfish

Damselfish have a number of different colors from red, yellow, and blue, depending on what type of Damselfish they are. They look similar to Cichlids.The Damselfish has a fork-shaped tail just like the Cichlid and a round-shaped body. 

Yellowtail Damselfish

The Yellowtail Damselfish has a blue body and a bright yellow tail. They grow to about 3 inches long and are among the few peaceful Damselfish.

Blue Damselfish

They are blue but the males tend to have a yellow mouth and tail. It’s also interesting to note that when the Blue Damselfish is scared, they can turn completely black as a defense mechanism. The Blue Damselfish grows to a maximum length of about 3 inches.

Bicolor Damselfish

They originate from the Caribbean Ocean and have an interesting color pattern on their bodies. The front of their bodies, and usually the top part are black. Below and behind the black their body turns yellow, and then closer to the tail they become white.

This particular Damselfish grows to about 4 inches in length.

Domino Damselfish

The Domino Damsel is also called the Three Spot because of their unique black body with white spots. They grow to about 5 inches in length.

Azure Damselfish

As you can likely guess by the name, this fish is blue. Blue on the top part and bright yellow on the lower part of the body near their stomach. The fish grows to about 3 inches in length and is also known as the Half-Blue Damselfish.

Temperament of Damselfish

a close up of a Damselfish swimming

Most Damselfish and especially the Domino Damsel are very aggressive fish. They also tend to be very territorial and will defend its space fiercely. Damselfish mainly attack peaceful fish that don’t fight back. The fights may lead to the targeted fish becoming stressed or even sick.

Tank Conditions

Tank size

In their natural habitat, Damselfish live in coral reefs and, if possible, it’s a great idea to place them in a reef tank to mimic their natural home. They should have at least a 30 gallon tank for the smaller Damselfish.

If you want to have a school of 4 or more, then they should be put in a tank that’s at least 100 gallons. For only 2 Damselfish in a tank, then a 50 gallon tank should be fine. Remember Damselfish can become more aggressive if they feel confined in a small space especially with other fish.

Water conditions

Damselfish can adapt to a wide range of water conditions because they’re very tolerant to fluctuations. Their water temperature should be kept between 73°F and 81°F, and the pH should be kept between 8.1 and 8.4.


Thisy like to have a sand substrate because Damselfish enjoy burrowing in it, especially at night. Damselfish prefer to have plenty of hiding places like caves, plants with large leaves, and other hollow spaces. With plenty of hiding places in their tank, territory wars are reduced significantly because the decorations reduce contact with other fish.

Tank Maintenance

a blue and yellow Damselfish swimming in a dark aquarium

A weekly checkup on the filters should be performed to make sure they are still working efficiently. It’s also a good idea to check on the water temperatures daily by placing a thermometer at the end of the aquarium furthest from the water heater.

The water quality should be looked at each week. Use water testing kits to confirm that nitrate, nitrite, and ammonia levels remain close to zero. A 15 percent water change should be done each week to maintain the water quality. 

Damselfish aren’t messy fish compared to other fish which is the reason why they don’t need large water changes. The Damselfish even eats algae growing in the tank helping keep the water clean. If you have other fish in their tank you may need larger water changes.

Best Tank mates for Damselfish

By now you already know that they are very aggressive fish. They have even been known to bite the hands of caregivers during feeding. Choosing tank mates should be done wisely to avoid pairing this fish with others that it may bully.

It’s important that your Damselfish are only paired with others of their same type. This means that Domino Damselfish can only be placed with Domino Damselfish. Blue Damselfish should not be kept together with a Yellowtail Damselfish or they could fight to death. Remember Damselfish are protective of their territory.

Damselfish can live with other fish species but avoid placing timid ones with them or they could become stressed from the bullying. Here are some fish species that make good tank mates for the Damselfish.

Since the Damselfish are more aggressive compared to all the above listed fish, always place them into the tank last. By placing Damselfish last, it reduces the level of aggressiveness because the fish learns to share the space from the beginning.

Health Issues

Damselfish rarely become ill unless exposed to poor water conditions or overcrowded tanks causing stress. Here are general signs of a sick Damselfish.

  • Damaged fins
  • Cloudy eyes and slimy body
  • Abnormal swimming patterns
  • Hiding most of the time
  • Not eating
  • Weight loss

Here are some of the most common illnesses that attack Damselfish.

Marine Ich

Marine Ich, also known as White Spot Disease, is a common parasitic disease that affects saltwater fish. It’s caused by the ciliate protozoan parasite and Cryptocaryon irritans, which attach themselves to a fish’s skin and gills.

Marine Ich is very contagious and can spread quickly through an aquarium. It’s often introduced into an aquarium through new fish or contaminated equipment. Poor water quality and stress can also weaken a fish’s immune system, making them more susceptible to the disease.

Symptoms of Marine Ich

Symptoms of Marine Ich include:

  • White spots on the skin and fins of infected fish
  • Rubbing against objects in the aquarium

As the disease progresses, fish can become lethargic and lose their appetite.

Fin Rot

Saltwater fish are prone to various diseases, and one of the most common ailments is fin rot. Fin rot is a bacterial infection that affects a fish’s fins, causing them to deteriorate and even fall off in severe cases. This condition can cause discomfort for fish and lead to further complications if left untreated.

The bacteria responsible for fin rot are opportunistic pathogens that thrive in poor water conditions, like low oxygen levels or high ammonia and nitrite levels. Stress can also be a contributing factor, because it weakens the fish’s immune system and makes them more susceptible to infections.

a pile of colorful fish flakes

Feeding Damselfish

Most Damselfish are omnivores and can eat commercial fish flakes, vegetables, living, or frozen foods. Some Damselfish are herbivores and it’s wise to consult the breeder or pet store owner before buying and finding out more about your new fish. Here are some of the best foods for your omnivorous Damselfish.

  • Brine shrimp
  • Copepods
  • Worms
  • Small fish
  • Worms
  • Shrimp
  • Finely shredded vegetables such as spinach, carrots, peas

If you have a community tank, you’ll realize that the bigger Damselfish eat from near the surface of the aquarium while the smaller ones eat from the bottom of the tank. The behavior likely has to do with the territorial nature of the fish.

Feed your fish 1 to 3 times a day and only give enough that they can eat right away to avoid having leftovers that can quickly contaminate the water in the tank. If you are feeding them frozen foods, it is better to thaw them first before feeding your Damselfish. If you find that your Damselfish are a bit aggressive you might want to feed them more. Fish that are well fed are less aggressive compared to hungry fish.

Related Questions:

Is it Possible to Breed Damselfish in an Aquarium?

The short answer is yes. They can breed in the aquarium if placed in pairs. This can be hard because you cannot really differentiate between male and female Damselfish because they look similar. One of the bigger problems is that you can put two of the same sex together and not even know.

A male Damselfish usually prepares a nesting site whenever it wants to spawn which attracts the females. After spawning, the male protects the eggs from predators until they hatch which happens after 4 to 5 days. 

After hatching, the fries grow fast and can survive in a tank as long as optimal water conditions are maintained.

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Contributing Author & Social Media Expert

Maryna is an animal expert that has had dozens of animals in her life over the years. She has never found an animal that she didn't love immediately. It seems like every year she finds kittens that have been abandoned by their mom and she nurses them to health and finds homes for them. She contributes her vast knowledge about animals and family pets to our website and we're forever grateful to have her working with us. She's also an amazing graphics designer and has designed all of the social media images that we use across all platforms.