Sim's Betta, Betta simorum

4abd71a1-979a-468b-aed1-9c7b7099b5de

Editor's Picks
Features Post
The brightest pupils
04 October 2021
Features Post
Dealing with egg ‘fungus’
04 October 2021
Features Post
Rathbun’s tetra in the wild
13 September 2021
Fishkeeping News Post
Report: 2021 BKKS National Koi Show results
13 September 2021
Features Post
The World's forgotten fishes
16 August 2021
Sim's Betta, Betta simorum
 

Andrew Smith discusses the sporadically seen but beautiful Betta simorum.

Common name:Sim's Betta

Scientific name:Betta simorum

Origin:Jambi and Riau in Sumatra.

Habitat:Among leaf litter in the shallow peat swamps with a low pH of 3.0-4.0.

Size:Up to 10cm/4"

Price:On sale for 6

Aquarium:I kept four semi-adult fish in a 45x30x30cm/18"x12"x12" planted tank. Given their size, put pairs in a 60x30x30/24"x23"x12" tank if you are thinking of putting other fishes in with them.

Water:pH 5.5-6.5 is fine, 22-28C/72-82F.

Diet:Wild fish feed on dragonfly and damselfly larvae. Aquarium fish take flakes, while glassworm, bloodworm and black mosquito larvae are good for conditioning.

Breeding:The male builds a large bubblenest among floating plants and can be aggressive, so spawn in pairs only. He looks after the fry until they are free-swimming. Just before, remove the nest to another tank. Feed fry infusorians for a day or two, then brineshrimp.

Notes:This species was described as B.simorum by Heok Hui Tan and Dr Peter Ngin 1996. it is named after fish collector Thomas Sim, who along with his wife collected it in the wild using baited cages. Closely related to Betta bellica. There are a number of differences, but the more obvious ones are the sloping profile to the head and the elongated pelvic fins.

Under strong light, the fish look washed out and show their displeasure by displaying longitundinal stripes on the body ( a junior synonym for B.bellica once was B.fasciata.) Subdued lighting will bring out the colouration ot the full.

The body is basically light brown, but the scales are resplendent in both sexes showing iridescent green. If you keep them in a species-only tank, try shading one end from overhead lighting.

The tailfin, shaped like the ace of spades in mature males, can propel them into orbit, it seems! Keep a well-fitting lid on the tank.

Availability:these fish were on sale at Wholesale Tropicals, London, and are only sporadically seen in the trade. The Anabantoid Association of Great Britain may be able to assist in sourcing fish.