Marine Betta Fish Care: Comprehensive Guide to Tank Setup, Diet & More

When I first started keeping marine betta fish, I was amazed by their striking appearance and unique behaviors. Caring for these fascinating creatures requires understanding the essentials of tank setup, diet, tank mates, and potential diseases.

One important aspect of caring for marine betta fish is creating a suitable environment. A well-planned tank setup ensures their comfort and promotes healthy growth. In my experience, it’s crucial to include plenty of hiding spots and live rock to mimic their natural habitat.

Marine Betta fish require a tank size of at least 30 gallons, with a temperature range of 72-78°F and a pH range of 8.1-8.4. They are carnivores and need a varied diet of high-quality frozen or live foods such as brine shrimp, mysis shrimp, and krill. They also require a well-lit aquarium with plenty of hiding places and live rock. Regular water changes and tank maintenance are important for their health.

Another aspect to consider is their diet. Since I learned that marine bettas are carnivorous, I ensure they are fed a variety of high-quality protein sources. Having the right tank mates also plays a role in their well-being, as some species may not coexist peacefully. With proper care, you can enjoy the beauty of these magnificent fish for many years.

Marine Betta Comet Fish

Species Summary


The Marine Betta, also known as Comet, is one of the most fascinating fish species. They are native to the Indo-Pacific region. I remember when I first saw them, I was amazed by their vibrant colors.


Marine Bettas have a relatively long lifespan of up to 8 years, which I find to be great for those who want a long-term aquatic pet.


These amazing fish have a distinct appearance, sporting a dark blackish-blue body with white spots. The pattern gives them an otherworldly look, which I always find mesmerizing.


Marine Bettas tend to grow up to six inches. In my opinion, their moderate size makes them suitable for various tank setups.

Growth Rate

The growth rate of Marine Bettas is moderate. From my experience, it usually takes them around a year to reach their full size.

Behavior & Temperament

When it comes to behavior, Marine Bettas are known for being shy and solitary creatures. They usually hide in the rocks and caves during the day. I’ve observed that they become active nocturnal predators once the lights are dimmed.

Male vs Female

Sexing Marine Bettas can be a bit tricky, as males and females look similar. However, a key difference lies in their ventral fins– the males have more elongated and filamentous fins compared to the females.

Tank Setup

Tank Size

When I set up my marine betta fish tank, I followed the general rule of thumb: a 30-gallon tank is the minimum to comfortably accommodate one fish. This size allows enough swimming space and helps maintain stable water parameters.


I found that marine bettas prefer dimmer environments due to their nocturnal nature. So, I set up low-intensity LED lights to mimic their natural habitat while allowing me to enjoy their beauty.

Filtration & Aeration

Marine bettas need excellent water quality to thrive. I chose a powerful filtration system to remove waste and provide biological filtration. Additionally, an air pump dramatically improved water circulation and aeration.


As these fish prefer warmer temperatures, I installed a reliable heater in my tank. I set the temperature between 75°F and 80°F, keeping my marine bettas content and healthy.


I opted for a fine sand substrate to replicate their natural seabed environment. This choice provides comfort and encourages natural behavior, like burrowing.


I provided ample hiding spaces and areas to explore, using rocks, caves, and PVC pipes. As a result, my marine bettas felt secure and displayed more fascinating behaviors.


I introduced some live plants, such as Java Fern and Anubias, which added a natural touch to the tank and improved water quality. They also provided additional hiding spots for my marine bettas.

Water Quality

Water Temperature

Maintaining a stable water temperature is essential for Marine Betta fish. I’ve found that my fish thrive in water temperatures of 75-80°F (24-26°C). It’s essential to use a heater and a thermometer to monitor the temperature in your tank.

Water pH

Similarly, the correct pH levels enhance the well-being of these delicate fish. I aim for a pH range of 8.1-8.4 for my Marine Betta tank, as they prefer slightly alkaline water. Regular water tests can help ensure that your pH stays within this range.

Water Hardness

For Marine Betta fish, water hardness is another important parameter. I maintain a specific gravity between 1.020-1.025 and an Alkalinity of 8-12 dKH. This will provide an ideal environment for the fish to grow and remain healthy.

Water Changes

Regular water changes help keep my Marine Betta fish healthy as it helps eliminate toxins and waste. I perform about 20% water change every 2 weeks in my tank. Doing this consistently will help prevent any unwanted fluctuations in water quality.

Tank Maintenance

When I first set up my marine betta tank, I quickly learned that regularly maintaining the water parameters is crucial for their well-being. Keeping the water clean helps prevent common diseases and makes for a healthy environment.

To achieve this, I change 15-20% of the water every two weeks. It’s essential to use reverse osmosis water to prevent any harmful elements from entering the tank.

Testing the water is another important aspect of tank maintenance. I always make sure to check the pH, nitrate, and ammonia levels. For bettas, it’s best to maintain a pH level of 8.0 – 8.4, and I aim to keep the nitrate and ammonia levels as close to 0 ppm as possible.

I find using live rock helpful in maintaining water quality, as it hosts beneficial bacteria essential for the nitrogen cycle in the aquarium.

Regularly cleaning the tank equipment is also crucial. I pay special attention to the filter and protein skimmer, as they help remove waste and maintain water quality.

Here are some essential points to remember when maintaining your marine betta tank:

  • Change 15-20% of the water every two weeks
  • Test the water regularly
  • Maintain a pH level of 8.0 – 8.4
  • Ensure nitrate and ammonia levels are close to 0 ppm
  • Use live rock in the tank
  • Clean the tank equipment

From my personal experience, maintaining a marine betta tank in this manner helps ensure the fish remain healthy, happy, and thrive in their environment.

Tank Mates

Compatible Fish Species

When I was setting up my marine betta tank, I learned that these fish can be quite peaceful with the right tank mates. They generally coexist well with other non-aggressive species that won’t outcompete them for food or territory. Some suitable options are:

  • Clownfish
  • Dwarf angelfish
  • Filefish
  • Gobies
  • Tangs

In my experience, these fish tend to share the same temperament as the marine betta, enabling them to live harmoniously together.

Incompatible Fish Species

However, you should avoid aggressive or overly active species, as they can stress out or even harm your marine betta. In my tank, I’ve avoided the following fish:

  • Large angelfish
  • Triggerfish
  • Lionfish
  • Groupers
  • Eels

By being careful with your selection of tank mates, your marine betta will feel more at ease and display its best behavior, making your aquarium a beautiful and harmonious ecosystem.


What To Feed

As a marine betta fish owner, I’ve discovered that these beautiful fish are carnivorous and require a meat-based diet. I mostly feed mine a variety of marine-approved frozen, flaky, and live foods. Some of the types of food I recommend include:

  • Brine shrimp: Both live and frozen varieties are great options.
  • Mysis shrimp: A highly nutritious and readily available food choice.
  • Squid and clam: Chopped into bite-sized pieces for easier consumption.
  • Marine pellets: High-quality pellets can balance their diet.


I’ve found it best to feed my marine betta fish once or twice per day. It’s important not to overfeed them, as it can lead to health issues.

Feeding tips:

  • Use a feeding stick to target-feed and ensure they don’t miss out on the food.
  • Monitor their feeding habits to help prevent overfeeding or underfeeding.


Here are a few tips I’ve learned to help keep my marine betta fish happy and healthy:

  1. Variety is key: Give them different types of food to maintain a balanced and diverse diet.
  2. Observe their behavior: Check for any changes in their eating habits or physical appearance to detect potential health issues.
  3. Avoid using copper-based medications, as they can be harmful to marine betta fish.

Remember to maintain a clean tank environment, as well as provide hiding spots, to ensure the overall wellness of your marine betta fish.

Common Diseases


In my experience with marine betta fish, I’ve encountered a few common diseases that may affect their overall health.

  1. Ich: Caused by a parasite, commonly affects many marine fish.
  2. Fin rot: A bacterial infection that causes fins to deteriorate.
  3. Velvet: A parasitic infection often seen in marine fish.


To identify these diseases early, it’s crucial to be aware of their symptoms.

  • Ich: White spots on the fish’s body, scratching against tank items, and lethargic behavior.
  • Fin rot: Ragged, discolored fins, and occasionally a lack of appetite.
  • Velvet: Dusty or golden appearance on the fish’s skin, labored breathing, and clamped fins.


When my marine betta fish show signs of illness, I take immediate action for their recovery.

  • Ich: Raise the tank temperature slightly, treat with copper-based medications, and maintain stable water quality.
  • Fin rot: Remove the affected fish to a quarantine tank, use antibiotics, and keep optimal water conditions.
  • Velvet: Treat the aquarium with a copper-based medication, ensure good water quality, and maintain proper nutrition.


The key to having healthy marine betta fish lies in proper prevention strategies.

  • Maintain high water quality with regular water changes.
  • Keep a well-balanced diet for the fish.
  • Avoid overstocking the aquarium.
  • Quarantine new fish before introducing them to the main tank.

Signs of a Healthy Marine Betta

I always look for certain indicators to ensure that my marine betta is healthy. Below are some key signs that you should monitor regularly.

  1. Active Swimming: A healthy marine betta will be cruising around the tank, exploring its environment. It’s perfectly normal for them to be more active during the night, as they are nocturnal creatures.
  2. Vibrant colors: My marine betta has bright and crisp colors that look absolutely stunning. If your fish has healthy colors, it’s a good indicator of overall wellbeing.
  3. Properly functioning fins: When I observe my marine betta swimming, I ensure that all its fins are moving in their normal manner. Clamped or torn fins are signs of potential health issues.
  4. Feeding well: A healthy appetite is fundamental to a marine betta’s wellbeing. Keep an eye out for any changes to your fish’s eating habits.
  5. Clear eyes: A marine betta’s eyes should be clear and bright, without any signs of cloudiness or swelling.
  6. Healthy slime coat: Marine bettas have a slime coat that helps protect them from infections. You should not see any excess slime or a peeling appearance.
  7. Consistent breathing: A healthy marine betta will have a regular breathing rate, without any signs of labored or rapid breathing.

When I maintain a high-quality living environment for my marine betta, it thrives and displays all these healthy signs. Remember, a happy and healthy marine betta is a true testament to your dedication as an aquarist.

Signs Your Marine Betta is Sick

I remember when I first noticed my marine betta acting a little “off”. It was displaying some behaviors that had me concerned. Here are some common signs to look out for in a sick marine betta fish:

  1. Loss of appetite: If your fish is refusing to eat or has a noticeable change in eating habits, it could be an indication of illness.
  2. Lethargy: A healthy marine betta is usually quite active. If you find yours being unusually sluggish or resting in one place more than usual, it’s time to investigate further.
  3. Changes in swimming behavior: Erratic swimming, loss of balance, or swim bladder issues can all signal that something is wrong with your fish.
  4. Physical deformities: Keep an eye out for any physical changes in your fish like swollen eyes, clamped fins, or bloating.

Additionally, there are other symptoms to watch for:

  • Bumps, spots, or parasites on the body
  • Unusual coloration or loss of color
  • Rapid breathing or difficulty breathing

Prompt action will often make a difference in your marine betta’s recovery. In my case, I was able to consult with an expert and provide proper treatment for my fish to return to its normal, healthy state. Stay vigilant, pay attention to your marine betta’s behavior, and you can help ensure its wellbeing for years to come.


Marine Betta Comet Fish 2

Breeding Setup

When I decided to breed my marine betta fish, I had to first create a separate breeding tank. It was important to mimic the natural habitat, so I used a mix of live rock, sand, and caves. I maintained a stable temperature around 78-80°F (25-27°C) and a salinity of 1.023-1.025.

How To Breed

To encourage my marine bettas to breed, I fed them a varied diet of live and frozen food, enriching their overall health. During spawning, the male fish guarded the eggs while the female swam nearby. They laid eggs in a hidden, dark area such as a cave.


After about 10 days, I noticed the eggs hatching into larvae. Feeding them was a challenge, so I used rotifers as their initial diet. As they grew, I progressed to Artemia nauplii. It was crucial to keep the water quality pristine, performing regular water changes and monitoring the levels of ammonia, nitrites, and nitrates.

Product recommendations for Marine Betta:

  1. AquaIllumination Hydra 32 HD LED Light Fixturee: This high-quality LED light fixture can provide the perfect lighting for your Marine Betta tank.
  2. CaribSea Arag-Alive Fiji Pink Sand: This sand substrate is perfect for creating a natural-looking environment for your Marine Betta.
  3. Instant Ocean Sea Salt: This high-quality sea salt mix can help you create the perfect water conditions for your Marine Betta.
  4. API Aquarium Test Kit: Regular water testing is crucial for maintaining a healthy environment for your Marine Betta, and this test kit can help you monitor the levels of ammonia, nitrite, and nitrate in your tank.
  5. Hydor Koralia Nano Aquarium Circulation Pump: This compact and efficient pump can help improve water circulation in your aquarium and provide your Marine Betta with a more natural environment.
  6. Seachem Stability: This beneficial bacteria supplement can help establish a healthy biological filtration system in your Marine Betta tank.
  7. Coralife BioCube Protein Skimmer: This protein skimmer can help remove organic waste from the water and keep your Marine Betta tank clean and healthy.
  8. AquaFX Barracuda RO/DI System: This high-quality water filtration system can help you create the perfect water conditions for your Marine Betta.
  9. Hikari Marine A Pellets: These pellets are specially formulated for marine fish like the Marine Betta and contain high levels of protein and other essential nutrients for healthy growth and vibrant coloration.


Having a Marine Betta fish can be a rewarding experience for any aquarium enthusiast. Personally, I found it to be a beautiful and enjoyable addition to my saltwater aquarium.

By providing a proper tank setup with hiding spots and a stable environment, the Marine Betta can thrive. It is essential to provide them with a varied diet for optimal health.

Moreover, compatible tank mates must be chosen carefully to ensure a peaceful coexistence. Beware of any potential diseases, monitor your fish’s health regularly, and act promptly if something seems off.

With proper care and attention to detail, having a Marine Betta fish can be a fantastic and captivating adventure. I hope my experience and fascination with these creatures can inspire you to consider adding a Marine Betta fish to your aquarium journey.


What size tank do marine betta fish need?
I recommend a minimum tank size of 30 gallons, though larger is always better as it helps the fish feel more secure and allows them to develop naturally.

Can marine betta fish live with other species?
Yes, they can! They are generally peaceful community fish. Slow-moving, non-aggressive, and similar-size tank mates are ideal.

What do they eat?
Marine bettas are carnivorous. In my experience, feeding them a varied diet that includes live or frozen brine shrimp, mysis shrimp, or chopped seafood has shown positive results.

Are marine betta fish hardy and disease resistant?
In general, they are; however, maintaining proper water quality is essential to prevent diseases. Knowing the signs of diseases, such as fin rot or ich, is crucial to act quickly in case of a problem.

How often should I do water changes?
For maintaining the tank environment, I personally perform 10-15% water changes weekly. This helps keep the water parameters within a safe range for my marine betta fish.

Do marine betta fish need hiding spots?
Yes, they absolutely do! They are quite shy by nature. In my tank, I have created numerous hiding spots using caves, rock formations, and PVC pipes for them.

What specific water parameters should I maintain?
Optimal parameters include a temperature between 72-78°F, pH between 8.1-8.4, and salinity between 1.020-1.025. Monitoring these parameters is key to maintaining a balanced environment in my marine betta tank.

Do marine betta fish exhibit any interesting behaviors? I’ve observed that they are nocturnal creatures that like to come out in low-light settings. They are also very adaptive and can change their coloration to blend in with their surroundings.

Reference: Wikipedia.


Hi there! My name is Jacob, and I'm the founder of this Pet people blog that talks all about aquarium and fishkeeping. I've been passionate about fish and aquatic life since I was a kid, and I've spent countless hours learning about different species, their habitats, and how to create the perfect environment for them to thrive in.

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