A 100-gallon fish tank typically measures 72 inches long, 18 inches wide, and 20 inches high.

A standard 100-gallon aquarium has dimensions of 72" x 18" x 20" (L x W x H), though exact measurements vary by manufacturer. These tanks weigh approximately 180 pounds empty and 900 pounds when filled with water, requiring sturdy stands and proper floor support.

Common 100-gallon tank dimensions comparison

Brand/Model Length Width Height
Standard rectangular 72" 18" 20"
Extra-tall 60" 18" 24"
Show tank 72" 24" 16"

Setup considerations for 100-gallon tanks

  • Floor support: Must support 900+ pounds when filled
  • Equipment: Requires 200-300W heater, 300-500 GPH filter
  • Space needed: Allow 6-12 inches clearance on all sides
  • Stand dimensions: Typically 72" x 18" x 30-36" tall

Popular fish for 100-gallon aquariums

  1. Cichlids: 10-15 medium-sized African or South American species
  2. Community fish: Schools of tetras, barbs, or rainbowfish
  3. Large species: Single Oscar, discus group, or small predator fish
  4. Marine options: Small reef setup with clownfish, gobies, and corals