Black Tiger Swordtail (Xiphophorus hellerii var. "Black") Large (Aquarium Glaser)

Black Tiger Swordtail XL (Xiphophorus hellerii var. "Black") is a striking and robust livebearer, selectively bred for its deep black coloration and large size. 

Appearance & Traits

• Coloration: Jet-black body with a sleek, streamlined profile. The "Tiger" name may refer to subtle striping or enhanced contrast in some variants.
• Size: XL specimens can reach up to 14 cm (5.5 inches) 
• Sexual Dimorphism:
  • Males: Feature a long sword-like extension on the lower caudal fin and a gonopodium.
  • Females: Larger, rounder, and lack the sword extension 

Tank Requirements

• Minimum Tank Size: 30 gallons for a small group; larger tanks preferred for breeding or mixed setups 
• Water Parameters:
  • Temperature: 72–79°F (22–26°C); tolerates 65–82°F range 
  • pH: 7.0–8.2 (slightly alkaline)
  • Hardness: 12–30 dGH
• Aquascaping:
  • Include plants, rock-based decor, and open swimming space
  • Avoid excessive driftwood (can lower pH)
  • Use a secure lid—Swordtails are known jumpers

Diet

• Omnivorous: Thrive on a varied diet including:
  • High-quality flakes and pellets
  • Frozen/live foods: brine shrimp, bloodworms, daphnia
  • Vegetables: spirulina, blanched spinach, zucchini
• Feed 1–2 times daily; juveniles may need up to 3 feedings

Behavior & Compatibility

• Temperament: Peaceful but territorial males—best kept with more females than males (e.g., 3–4 females per male) 
• Tank Mates:
  • Good: Platies, mollies, guppies, corydoras, rasboras, danios
  • Avoid: Aggressive or fin-nipping species
• Social: Not true schoolers but prefer group living

Breeding

• Livebearers: Females give birth to 20–50 fry every 4–6 weeks 
• Fry Care:
  • Use dense plants or breeding boxes for fry protection
  • Feed fry protein-rich micro foods like baby brine shrimp
  • Adults may eat fry if not separated