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Betta splendens

Betta spl. male halfmoon blue - Betta Fish for Sale UK

Moderate Care
Semi-Aggressive
£30.99Sold Out

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Live arrival guaranteed. If they don’t arrive healthy, email us a short unboxing video the same day for a replacement or refund. Packed in oxygenated bags with insulation and heat packs when needed.
£19.95 tracked delivery — half price (£9.98) from £100.00, free from £200.00. One delivery charge however many fish you add — everything travels together with a licensed live-animal courier.
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A striking long-finned male betta with vivid blue coloration and elegant halfmoon tail form, ideal for a warm, peaceful species tank. Moderate care, semi-aggressive. 24-30C, pH 6.0-7.5.

Care at a Glance

Scientific Name
Betta splendens
Max Adult Size
up to 6.5 cm
Lifespan
3 years
Care Level
Moderate
Temperament
Semi-aggressive
Temperature
24–30°C
pH Range
6–7.5
Hardness
1–15 dGH
Minimum Tank
40L
Diet
Carnivore

Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller. Product-photo provenance and any image-specific limitations are stated on the listing.

Similar choices available now

Blue and red male Betta splendens swimming side-on in an aquarium
Full Care Guide

Betta Fish Care Guide: Siamese Fighting Fish

For one typical domestic Betta splendens, start with at least 20 litres, a mature filter, thermostatic heater, separate thermometer, gentle flow, a secure lid with surface access, and plants or refuges. Keep one male per aquarium.

13 min readRead guide

Water Parameters

Maintain these water conditions for optimal health and vibrant colors

Temperature
24–30°C
24°CIdeal30°C
pH Level
6–7.5
6Ideal7.5
Water Hardness
1–15 dGH
1 dGHIdeal15 dGH

Ask ten keepers to picture a show betta and most will describe this fish: a blue halfmoon male, tail spreading to its full half-circle, body and finnage in the deep blue that has anchored the hobby for decades. Ours arrive at around 6.5 cm with the halfmoon spread already established — a finished show fish rather than a grow-out project.

Two things make this listing slightly gentler than it looks. First, the line is graded semi-aggressive rather than fully aggressive; second, his needs are simple enough that the moderate care rating mostly comes down to consistency. That said, the company rules barely relax: snails are safe, peaceful shrimp may work in heavily planted tanks though they can be hunted, and the avoid list keeps out other male bettas, fin-nippers, aggressive or highly territorial species, large predators, and brightly coloured long-finned fish that read to him as competition. Recorded housing: a 40-litre minimum, 24–30 °C, pH 6.0–7.5, hardness 1–15 dGH. He frequents the upper layer of the aquarium, displays best in still water, and grows more territorial if conditioned toward breeding.

Settling a show male is a one-week project done well. Acclimatise slowly, light the tank gently at first, and feed sparingly for the first two days — appetite is the signal that he has accepted the move. From there his moderate rating runs on routine: carnivore meals, weekly changes holding pH 6.0–7.5 and hardness 1–15 dGH, heater steady anywhere across his wide 24–30 °C tolerance. The 40-litre minimum gives the spread room and gives you aquascaping latitude below the surface zone he actually uses. Classic blues hold their colour with little intervention, which is partly why the strain endures: he looks after the display side of the arrangement, you look after the water.

Blue halfmoon vital statistics

  • About 6.5 cm adult size
  • Circa 3-year lifespan
  • Care level moderate
  • Semi-aggressive disposition
  • 24–30 °C range
  • pH 6.0 through 7.5
  • 1–15 dGH water
  • Minimum 40 litres
  • Carnivorous menu
  • Top-water habits

Ordering yours

This is the strain we recommend when someone wants one definitive show betta. He travels UK-wide by licensed live-animal courier in insulated packaging, with our live arrival guarantee as standard.

Customer Reviews

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What customers say about ordering from us

  • 4 out of 5Verified buyer

    I have a small group of long finned mountain minnows. So was delighted to be able to order ten of this variety to increase the genetics in my tank . The ones I recieved are healthy but it’s to early to give a verdict on wether they are of a long finned type since they are small currently.

    Gordon Walker · 23 Sept 2026

  • 5 out of 5Verified buyer

    100% success travel and "installation". Pleased with quality of purchase. The Siamese fighter a bit "shy" so have not yet seen him at his best yet but looking good. Happy customer. GG

    George E Garratt · 21 Sept 2026

Reviews of our shop, collected by Judge.me, an independent third-party review collector. Newest first.