The Marine Betta or Comet is probably one of the most interesting of salt water fish!
The eye spot at the base of the dorsal fin fools prey into thinking the mouth of the fish is at the wrong end! When the Marine Betta or Comet hunts it approaches its prey sideways (very neat to watch) and when the prey tries to escape by way of the tail, it turns out ot be the mouth and the fish is caught! Another theory is that the eye spot resembles the head of a moray eel, a very good defense against predators.
The Marine Betta or Comet is harder to keep than other groupers since it much prefers live food and is slower to eat than many other aquarium fish. For this reason, It is recommended that this fish be kept as a single specimen or in a very sparsely populated tank!
For more Information on keeping this fish see:
Guide to a Happy, Healthy Marine Aquarium
Marine Betta Fry Juveniles (Calloplesiops altivelis)
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Video showing various stages of Marine Betta baby growth!
This video is from the company that has tank bred Marine Bettas! The fry at 16 days develop a big white spot on the sides of their bodies. This white spot is gone by 7 months old. These very peaceful fish only grow to about 7" and are compatible with most fish except the very small Green Clown Goby sized fish, aggressive or large fast moving fish that will keep them from coming out. A male and female will do well in a 75 gallon, but 2 males need a 6' tank!
marine betta eats live fish (Calloplesiops altivelis)
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Great video of the sized fish a Marine Betta will eat
This video shows how Marine Betta fish will hunt. It is a very quick catch in this case, but shrimp are more methodically hunted, making for an interest display! Only very small fish like Clown Gobies shouldn't be housed with your Marine Betta. Avoid aggressive fish and large fast moving fish that may prevent the Betta from getting enough food. This tank should have more ledges for the Marine Betta to hide under. The best tank mates are anthias, larger flasher wrasses, fairy wrasses, cardinal fish, small more peaceful hawkfish, more mellow dwarf angelfish, mellow chromis and larger mellow damsels, large gobies, larger blennies, jawfish and clownfish. Juveniles of these fish added after the Marine Betta is established may be eaten. Add your Marine Betta before your dwarf angelfish, which should be added last.
Maintenance difficulty: The Marine Betta or Comet is difficult to keep mainly because it needs special attention in order to eat. Although there may be cases where this fish will eat prepared foods, we have not seen it. Normally they will only eat live fish about the size of a guppy or very small goldfish.
They also need plenty of time to stalk and capture their prey. If they are in a tank with other predaceous fish, like lions and groupers, they will most likely starve because they are not fast enough to get a good share of the food.
Maintenance: Feed all kinds of live foods. If you are interested in trying prepared foods, squid, clams, shrimp, chopped fish, lancefish, or silversides. Although lionfish primarily eat live food also, many have been trained to eat lancefish or silversides in the aquarium.