Diet, Tank, Mates and Breeding

Added beautiful fish like the marine betta to your saltwater aquarium can be a good idea as long as you follow the tips shared in this guide, such as tank size, diet, and good companions. They are not very difficult to maintain, so we are confident to say that they are strong and pretty 🙂

The Marine Betta or Calloplesiops altivelis (scientific name), also known as Comet due to its fluttering fins (similar to Comet Goldfish) and nocturnal pattern, is a long-finned tropical fish native to the waters of the Indian and Pacific Oceans, ranging from the East Africa to Central Pacific south of Hawaii. They extend as far north as Japan and reach south to the Great Barrier Reef. Bettas live between 10 and 150 feet below the surface, clinging to pinnacle and lagoon reefs that provide plenty of hiding places.

Their gorgeous appearance compromises their rugged durability. Bettas are relatively slow-moving nocturnal predators that hide on the bottom of reefs. They herd their prey, attacking from the side. This tactic involves wedging the fish against coral or rock. The comet then extends its fins to encircle the fish, often leading to the meal swimming directly into the Betta’s claws.

Author’s note: Marine bettas are relatively shy and non-aggressive scale fish. When not hunting, they spend their time hiding among rocks and corals. They make up for their lack of aggressiveness with a unique natural adaptation.

Marine Bettas have a white-spotted body and a large eye-like dot near their caudal fin. When the fish dives headfirst into a rocky hole or opening, the exposed rear part of its body resembles the intimidating moray eel. This deception helps them survive in the wild and adds a dazzling touch to your tank.

Marine Bettas are dark brownish-black in color and are covered in white spots. Their pattern is so consistent that it is difficult to locate their eye as the iris is white, completing their natural camouflage. However, the eyes are large, allowing the fish to see better during their night hunts.

The comet’s uniform coloration makes it difficult for would-be predators to coordinate an attack. While the attacker determines the optimal place to bite the Marine Betta or takes the tail for the head due to the false eye, he has time to flee.

A marine betta or comet looking for food

The outline of the spot near the caudal fin and the edges of their other fins have a bright blue and orange color. The white dots fade to a pale blue tone near the dorsal and anal fins, which have bright blue stripes.

Author’s note: The pectoral fins are apparently oversized for the body of the fish, but allow for the corralling technique the Betta uses to hunt. The fins are transparent but have bright yellowish and blue lines stretching across them, creating a web-like appearance.

Biologists aren’t sure how long wild bettas live, but they can live ten years or more in captivity. Once you have conditioned the fish to feed, keeping them alive is simply a matter of maintaining low stress levels and optimal aquarium conditions.

The size of Marine Bettas can reach up to 8 inches long. Males are generally larger than females with slimmer bodies, but it can be difficult for even experienced fish keepers to sex fish.

Marine Bettas are relatively easy for fish to care for. While many seasoned aquarists appreciate them for their beauty, they are excellent fish for beginners because they are hardy and low maintenance.

While some claim that fish are difficult to feed, experts say that is a misconception. Bettas are slow and methodical hunters. They do not compete well with more aggressive fish for live prey or prepared foods.

tank size

Your Betta requires a 55 gallon or larger tank due to its relatively large size. Simulating their natural environment requires enough space at the reservoir bed to move around and hunt. Keep the current low. Comets are not active swimmers and spend most of their time lounging among rocks or calmly patrolling the bottom of the tank.

Author’s note: Blue lights are preferable to bright aquarium lights. Marine Bettas are nocturnal creatures that stay in the lower third of the tank to avoid intense light.

Water parameters

Bettas generally thrive in tanks once they have adapted. Standard tropical conditions are acceptable.

  • Water temperature: 72 to 82°F
  • pH levels: 8.1 to 8.4
  • Water hardness: 8 to 12 dKH
  • Specific gravity: 1.020 to 1.025 sg

Comets do best in reservoirs filled with living rock. They prefer to spend their days hiding as they are nocturnal predators. Position the rock pieces to allow the fish to explore, but keep them dense enough to provide adequate protection.

You can add caves, overhangs, and other hollow decorations that provide hiding space, but make sure they are large enough to accommodate the size of your Betta. These fish do not disturb corals and are harmless to reefs.

When placing the rock, make sure that the large pieces are firmly fixed. The comet could dislodge loose rocks as it explores, creating cave-ins that could crush them or other fish.

Bettas are excellent beginner fish because they are very resilient. Marine biologists believe that the mud covering their bodies has an antiparasitic effect. Comets are so durable that they will survive an outbreak of Cryptocaryon, which leads to marine ich, without ever contracting the disease. They usually recover from minor injuries without infection.

As with all fish, it is always recommended to ask the seller what specific diet your marine betta was fed at the store. While some comets are sold already packaged in flakes or pellets, most aquarists find that fish prefer live or frozen seafood. The challenge is to make sure the comet gets its share of the food you provide to the tank community. Its unique hunting style means it won’t compete with aggressive hunters for prey or prepared food.

Author’s note: Quarantining your fish before introducing them to your aquarium will help condition them for food. Experts suggest providing enriched brine shrimp, scallops, fresh fish, chopped shrimp, baby shrimp, or frozen foods.

Introducing food to them using a feeding stick is the best tactic. Shaking the meal at the opening of their hiding place tricks them into thinking the food is alive and prompts them to dine. Over time, the Comet will learn to accept dead fish provided in the original tank.

If your Betta is packaged in flakes or pellets, or you are successfully weaning them, opt for a carnivorous mix. The smell of these foods will attract the comet and the pellets will sink to the bottom of the tank, which is the fish’s natural hunting ground.

Other aquarists have reported success in providing live blackworms or mollies. Your comet will eat any small crustacean or fish that fits in its mouth. Timing your feedings at night or when you turn off the aquarium light can maximize your success, as this is when fish are naturally adapted to eat.


Marine betta swimming in a saltwater tank

Unlike the aggressive freshwater betta or Siamese fighting fish, comets are shy and docile. They will generally not interact with other fish, preferring to spend their time alone on the floor of your aquarium.

Aquascaping your aquarium to position hiding places that are still visible will maximize your ability to enjoy these superb fish. You can keep more than one Betta, but the males will fight if there isn’t enough space. Experts suggest that a tank of 6 feet or more is needed to provide adequate territory for multiple males.

Bettas are reserved and avoid other fish. Their size protects them from comparably sized predators, but they can become reclusive with aggressive fish and not compete for food. They generally do well with any common community fish or peaceful predators.

Suitable tank mates include:

  • Angelfish (like this Emperor Angelfish)
  • basslets
  • Butterflyfish (different from freshwater African butterflyfish)
  • Damsel
  • Engineer Gobies
  • Harlequin Tusk
  • Hawk fish
  • Shrimps and crabs too big to eat
  • small lionfish
  • Starfish
  • Tangs (like the Purple Tang)
  • Wrasses

Avoid small fish as the comet can eat anything that fits in its mouth, including shellfish.

Although keeping fish is always difficult, Marine Bettas are on the moderate end of the spectrum, which further enhances their value as an excellent starter fish. You can host a couple or a harem of the opposite sex. However, you will need a tank of 75 gallons or more for two comets and a tank of 125 gallons or more for a group.

Bettas are hermaphrodites. Depending on their genders at the time of purchase, the dominant fish will become male while the others will gradually transition to female. Adult males will be aggressive towards each other. It is generally best to buy females or young comets. Sorting out the social structure will be smoother and ensure the survival of all Bettas.

Author’s note: Although these fish can survive in a wide range of temperatures, keeping them above 78°F will promote breeding. You can also prime Comets to spawn by increasing the frequency of feedings.

It is best to use a breeding tank if you plan to breed Bettas. Once fertilized, the female will lay 500-1,000 eggs on a cave wall. The male then guards them until they hatch. The process can take up to two weeks, but the eggs usually hatch in five or six days.

Baby comets feed on rotifers and microscopic foods during their first few days. After a week they are large enough to eat live brine shrimp. You can also start them on pellets and flakes, conditioning them to a feeding routine. Young Bettas resemble adults except for a white patch on their tail fin. Their coloring changes to the darker tones of adulthood as they mature.

There you have it, a fine fish to add to your aquarium as long as you provide enough space to prevent aggression between other territorial fish. As their name suggests, Marine Bettas resemble Freshwater Black Bettas although a bit larger.

So, are you buying a Comet or do you already have one? Please share your story and let us know how it went!

Leave a Comment