Saltwater Aquarium Fish

Looking to keep saltwater fish in your aquarium? Here you’ll learn everything there is to know about how to accommodate them in your tank, along with the different species, the number of fish you can keep, and the different diseases that might affect saltwater aquarium fish.

The following are the two main steps you need to take to introduce saltwater aquarium fish to your tank. 

Cycle your tank before adding livestock to your saltwater fish tank

Of course, the very first steps will involve setting up your aquarium. Once you’ve done so, you can begin cycling the tank to prepare it for the addition of livestock. Cycling will make the water safe for fish and invertebrates.

Specifically, cycling involves building up beneficial bacteria in the tank that will help facilitate filtration. One type of bacteria will help convert toxic ammonia produced by fish waste into nitrites, which are also toxic. A second will help convert these nitrites into nitrates that aren’t as harmful.

You can begin cycling the tank by adding live rock or ammonia to the tank. Live rock is a popular option for cycling because it already has the bacteria needed to start the conversion process. If the live rock isn’t as effective as you’d hoped, you can also add some ammonia to begin the cycle.

Be sure to test the water once you’ve started to cycle the tank. You should see an increase in both ammonia and nitrite levels at first, after which they should gradually decrease to 0 ppm. A 50% water change can then further minimize any nitrate accumulation. This cycling process normally takes around six to eight weeks to complete. Increasing the oxygen levels and temp or adding filtration media from another aquarium can help accelerate the process.

Acclimate before adding saltwater aquarium fish to your tank

Before adding saltwater aquarium fish to your tank, you must acclimate them to ensure they are comfortable once they enter it. This is because fish are highly sensitive to changes in water temperature and the overall environment, making it necessary to help them adapt.

You can acclimate new saltwater aquarium fish in various ways, but the following is one popular strategy you can try:

  1. Keep your fish in the bag you bought them in and float it while closed on the surface of the aquarium water for around 15 minutes. This will help warm or cool the bag’s water to that of the aquarium.
  2. Open the bag while keeping it afloat on the surface of the aquarium water.
  3. Add half a cup of the aquarium’s water to the bag every four to five minutes and repeat the process until the bag is full.
  4. Pour half of the water in the bag into a bucket or another separate container.
  5. Begin adding half a cup of water from the aquarium to the bag, again repeating every four to five minutes until you’ve filled the bag.
  6. Start transferring the fish to the aquarium using a fish net. Once complete, empty the bag of any remaining water and dispose of it.

Proper feeding of saltwater aquarium fish

Not all saltwater fish follow the same feeding regimen, as they can be of many different species and might be carnivorous, herbivorous, or omnivorous. Make sure you learn about the different fish or other animals you have in your aquarium to determine how to feed them properly.

Some fish will feed on various organisms like plankton or krill that are often present in their natural environment. Meanwhile, you might need to feed others fish food such as pellets or flakes, which often contain fish-specific nutrients to help them stay healthy and grow.

Like with any other animal, avoid overfeeding your saltwater aquarium fish. By researching the fish’s diet and looking at instructions on fish food packaging, you can better determine when and how much to feed livestock.

Commons Saltwater Aquarium Fish Diseases

Depending on the habitat and the susceptibility of different fish species, saltwater fish could fall ill from various diseases. Some of the main types of saltwater aquarium fish diseases include:

  • Marine White Spot Disease — This disease, also called Marine Ich, forms small white spots on the fish’s body, including their gills and fins. It results from a Cryptocaryon irritans infection, and results in symptoms such as cloudy eyes, ragged fins, an increase in mucous production, and pale gills. Copper or a change in the salinity of the aquarium’s water may treat this disease.
  • Fin Rot — Fish may also experience fin rot, which is a type of bacterial infection that results from either abuse between fish or generally poor water conditions. It often develops when fish have their fins torn or ripped off by other fish. If the fins appear red or frayed, this could indicate fish rot. You may treat this infection by frequently changing the water to improve the habitat conditions, along with the use of antibacterial medication.
  • Lymphocystis — Also called cauliflower disease, this disease forms bumps on fish bodies that closely resemble cauliflower in shape and color. It can result from stress and poor water conditions. The spots may cover fins, skin, or gills. Although quarantining the infected fish may help prevent the spread of lymphocystis, the fish may have the infection for the rest of their life.
  • Tuberculosis — This is another common disease that tends to affect saltwater fish more than freshwater fish. Symptoms could include ulceration, fin erosion, skin reddening, lethargy, and loss of appetite. Poor water quality and unhealthy aquarium conditions could lead to this disease. While quarantining the infected fish can help treat it and keep it from spreading, it’s important to practice caution when handling them as this disease could infect humans.
  • Marine Velvet — This disease can spread quickly without sufficient treatment, which is why it’s so common among saltwater fish. An organism found in many saltwater aquariums, Amyloodinium ocellatum, causes this disease. Symptoms may include lethargy, signs of stress or irritation, and difficulty breathing, along with more visible symptoms such as gill inflammation that might result in bleeding. Copper can help treat this disease, but it’s important to identify and treat this illness quickly as it can very rapidly cause the fish’s condition to deteriorate.
  • Vibriosis — A bacteria called Vibrio could cause this internal infection in fish, which contract it through either dead fish or open sores. It’s often hard to detect until it reaches the later stages, as fish don’t exhibit any physical symptoms until the disease has progressed. Symptoms may include cloudy eyes, red streaks or spots on the body, and swollen, dark lesions. You should quarantine fish infected with this disease, but take care to avoid contamination as, like tuberculosis, you can contract this disease from fish.
  • Lateral Line Erosion — Fish with this disease tend to have defined pits on their heads, with these pits moving along the lateral line of the fish’s body. It’s not entirely clear what causes this disease, but one common feature that many infected fish exhibit is inadequate nutrition and generally poor health, either due to vitamin deficiencies or poor water quality. You may be able to treat this disease with dietary supplements and frequent water changes. 

Saltwater Fish Tank Care Guides

Do you need information on a specific type on fish for your saltwater aquarium? Each fish has different patterns and living habits We have all the requirements and reef safe information below in our care guides: 

List of Saltwater Aquarium fish

Angelfish

Anthias​

Assessors

Basslets

Blennies

Butterflyfish

Cardinalfish

Chromis

Clownfishes

  • 20 Best Clownfish For Saltwater Aquariums
  • Ocellaris clownfish
  • Tomato clownfish
  • Maroon clownfish
  • Picasso clownfish

Damselfishes

  • Blue Devil damselfish
  • Domino damselfish
  • Yellowtail damselfish

Dartfish

  • Firefish
  • Purple firefish

Dottybacks

  • Orchid dottyback

Dragonets

  • Mandarin dragonet
  • Ruby red dragonet

Dwarf angelfish

  • Flame angelfish
  • Bicolor Angelfish
  • Coral Beauty Angelfish

Eels

  • Snowflake Eel
  • Ribbon eel
  • Garden eel

Filefish

  • Aptasia eating Filefish
  • Scrawled Filefish
  • Orange Filefish
  • Unicorn Filefish

Gobies

  • 15 Best Goby’s For Saltwater Aquariums
  • Clown goby
  • Diamond goby (sleeper goby)
  • Engineer goby
  • Neon Goby
  • Firefish goby
  • Mandarin goby

Groupers

Hawkfish

Jawfishes

  • Blue spot jawfish
  • Yellow head jawfish

Lionfish

Moorish Idol

Pipefish

Pseudochromis

  • Pseudochromis fridmani

Pufferfish

Rabbitfishes

Squirrelfish

Tangs

Triggerfish

  • Clown triggerfish
  • Niger triggerfish
  • Picasso triggerfish
  • Queen triggerfish

Wrasses

  • Bluestreak cleaner wrasse
  • Christmas wrasse
  • Fairy wrasses
  • Leopard wrasse
  • Melanuras wrasse
  • Red Coris wrasse
  • Six line wrasse
  • Yellow coris wrasse

How Many Fish Can I Put in My Saltwater Aquarium?

There are multiple factors to consider when keeping fish in a saltwater aquarium, which is why there is no definitive answer to this question. However, generally, you can keep an inch of fish per five gallons of water in a saltwater tank. The size of the tank, the type of filtration system you use, and the species of fish and other animals you keep are a few key factors that will help determine how to stock your aquarium.

Saltwater Tank Stocking Guides:

If you are new and looking for a tank or if you have one already we have a guide for you. We can help you with rock-scaping and livestock ideas so you can find the best mix of compatible reef safe fish. Check out the stocking guides below: 

  • Best saltwater fish for a 10-gallon tank

  • Best saltwater fish for a 20-gallon tank

  • Best saltwater fish for a 30-gallon tank

  • Best saltwater fish for a 40-gallon tank

  • Best saltwater fish for a 50-gallon tank

  • Best saltwater fish for a 60-gallon tank

  • Best saltwater fish for a 70-gallon tank

  • Best saltwater fish for a 80-gallon tank

  • Best saltwater fish for a 90-gallon tank

  • Best saltwater fish for a 100+ gallon tank

Saltwater Fish Stores Online

Additional Information About Saltwater Fish