|Synonyms||Barrosia barrosi, Plesiops altivelis|
|Maximum Size||20cm (7.9")|
|Sexual Dimorphism||Unknown. There is speculation that the size and quantity of white dots on the body and fins are indicative of different sexes, but this is most likely just due to size (with younger specimens having fewer but larger spots compared to the adults).|
|Temperature||Tropical: 23-27 deg C (73-81 deg F)|
|Water Parameters||SG: 1.020-1.025, pH: 8.1-8.4|
|Compatibility||Reef with caution; Fish only with live rock|
|Lighting||Dim. If brighter lighting is to be used, ensure there are a multitude of dark hiding places.|
|Reef Aquarium Compatibility||Will not harm corals, but will eat ornamental shrimps and small fishes.|
The Marine Betta is known from coral reefs and drop-offs, to depths of 50m (164ft). Here, this reclusive, nocturnal species may be found hiding in dark caves and crevices by day, emerging at night to feed. In the home aquarium, this hardy, eye-catching fish is safe with corals, but does not appreciate the bright lighting that many sessile invertebrates require. If it is to be kept in a reef setting, ensure that there are a multitude of dark caves and crevices amongst the rockwork so that it can take refuge during the day, and preferably some areas of the tank that have more subdued lighting. Tankmates must be chosen with care, as adult Marine Bettas are capable of taking small fish and ornamental shrimps; however, they are a great choice for reef set-ups that contain corals and medium sized peaceful fish only. This fish behaves very shyly, especially when first introduced into the aquarium, but it can be coaxed out a little more if it is given adequate space, areas of subdued lighting/plenty of dark hidey-holes, and peaceful tankmates that are not too boisterous at feeding times. Unless the tank is very spacious, it is best to keep just a single specimen, unless you can acquire a compatible pair. A dim moon light that is run during the evening hours will allow you to view your Marine Betta as it goes about its business under the preferred subdued illumination. Interestingly, this species is a Batesian mimic of the Guineafowl Moray Eel (Gymnothorax meleagris). When threatened, the Marine Betta holds all its unpaired fins erect and swims headfirst into a crevice. Rather than swimming right into the hole, it stops part way in, with the posterior part of its body exposed. The back end of the Marine Betta, with fins held erect, resembles the shape of a moray eel's head. The white spotted pattern and the prominent ocellus on the dorsal fin further add to the illusion that it is a spotted moray eel peering out from a rock, and by appearing to be something dangerous, the 'moray eel' is then given a wide berth by would-be predators. May also be seen on sale as the Comet.
A newly imported Marine Betta may require live river shrimp, with gradual weaning onto frozen fare such as Mysis shrimp, vitamin-enriched brineshrimp, krill, chopped seafood etc. Unlikely to take dried foods. Offer at least one feed after lights out, target feeding if necessary. Observe carefully to make sure faster tankmates are not outcompeting this fish at meal times.
This species has been bred in the home aquarium. Little is known of the courtship behaviour, as this invariably takes place inside darkened caves and crevices. Up to 500 golden-brown eggs are deposited on the wall or roof of the chosen cave. The male fish guards the eggs, which should hatch within 5-6 days (temperature dependent). The resultant larvae are well-developed and begin feeding immediately. Initially dark in colour, they develop a large white patch on each flank, and it is some 6-7 months later before they display the adult pattern.