Good setups for a 100 gallon tank

Community setup

Four or five schools plus centrepiece and cleanup. Twenty to twenty-five tetras, fifteen to twenty rasboras or barbs, fifteen corydoras, a pair of angelfish or pearl gouramis, and a bristlenose or larger pleco. Or add rainbowfish, discus (with careful water management), or larger schooling fish. Canister or sump filtration. Track water parameters and maintenance schedules — App-aquatic helps with multi-tank logging.

Centerpiece setup

Four to six angelfish, thirty tetras, fifteen corys, and a pleco. Or a discus community with cardinal tetras and corys. Provide height and structure. Tall tanks suit angels; discus need stable, soft water.

Cichlid setup

100 gallons is ideal for African or South American cichlids. Malawi mbuna: eight to twelve compatible species with heavy rockwork. Tanganyika: frontosa, tropheus, or shell dwellers. South American: Severums, keyholes, or a pair of oscars with dithers. See types of cichlids. Match water chemistry; overstocking can reduce aggression in some African setups. Research species carefully.

General tips

Strong filtration, weekly water changes, and cycle before stocking. Add fish in groups. Respect bioload even in large tanks.

Quick takeaways

• 100 gallons suits large communities, multiple centrepieces, or full cichlid setups.
• Match species to water hardness; provide structure for territorial fish.
• Cycle first, stock gradually, maintain regularly.