There are so many fish that are attractive and tempt the aquarist, from small to moderate to large in size. Some are aggressive, some sensitive but are they suitable for the aquarium? The answer of course is mainly ‘yes’, with the addition that they all need to have their preferred environment provided.
One fish that is not as brightly coloured as some others, but is colourful and very attractive nevertheless, is the marine betta, as can be seen at the following link. Another common name for the fish is marine comet. The proper name is Calloplesiops altivelis.
The beta is covered in dots and has large finnage which is where the common names probably come from. When the fins are extended they look spectacular. These fish are capable of growing to around 6¼” (circa 16cm) so they are not for the small aquarium, if they are to be comfortably housed a 36″ (circa 91.5cm) aquarium or thereabouts is recommended. Normally only one beta should be kept. Their tank mates should be selected carefully as they are fairly shy and not at their best when housed with bold, high action and/or aggressive fish, the companions should be of a similar size or smaller. It is also best not to overcrowd the fish, which is good practice in any aquarium anyway – a lower fish population is advantageous.
Having said companions should be smaller, care is again needed as the beta could predate on much smaller fish. It tends to ambush them from whatever area it has decided to hide in. Care also needs to be taken with smaller crustaceans as these will sometimes be eaten.
Once the fish has settled in feeding is not normally a problem, good quality frozen food is usually accepted and often so is freeze dried food. There will no doubt always be exceptions, but flake food is not particularly attractive to them. The aquarist needs to observe the fish in the aquarium at feeding time, as is the practice anyway, as the beta could lose out to faster and greedier fish it is necessary to ensure it has fed sufficiently.
For the fish to settle well the aquarium must be furnished with rockwork, be this live rock or otherwise. The rockwork needs to be arranged so that there are one or two caves, preferably several, that are large enough for the fish to hide in and watch the outside world from.
A very bright halide lit reef aquarium is not ideal for the beta as it prefers moderate light – a reef that houses soft corals and is lit by fluorescents would be better, as would the lesser lit fish only system. The fish could become accustomed more or less to brighter light but in this circumstance is likely to hide away for longer periods. The natural habit of the fish is to hide away during the day, but in the lower lit aquarium the fish should be seen more often for longer periods.
When the fish is first introduced to the aquarium it is likely to hideaway for quite a period, most fish hideaway at first but the beta’s period could be longer. The fish should start to appear when ‘dusk’ occurs (that is, main lights off and actinics only on before lights out) or maybe it could be ‘dawn’. Whatever, it should settle provided it feels secure and the environment is of high quality and then be seen more.
The only defence the fish has (to my knowledge) is that when it feels threatened it will put its head into the rocks and leave only the tail and rear body showing. The markings on the rear end seem to be similar to a moray eel, and any potential aggressor will consider twice before mixing with those.
This lovely and interesting fish will be excellent for the aquarium provided its tank mates are suitable, the lighting isn’t too bright, there are suitable hiding places and the seawater is of high quality. The aquarist could need to search a little before a fish is located.