Best fish for a 100 gallon reef tank

Curated by the Fast Aquatics editorial team · Updated May 2026 · Sources

100 gallons is the smallest comfortable size for a mid-size reef community with one display tang and full peaceful stocking. Here's what fits.

Recommended stocking (10-12 fish)

1 Yellow Tang (the display herbivore) + 1 Kole Tang (algae grazer, different body shape) + 1 Ocellaris pair + 1 Royal Gramma + 2 Firefish (pair) + 1 Six-Line Wrasse + 1 Mandarin Goby (after 6+ months copepod buildup) + 1 Lawnmower Blenny + 3-5 Banggai or Pajama Cardinals.

Total: ~12 fish in a 100g. Bioload-conservative for a mixed reef with corals.

What does NOT fit in 100g

Naso tang (needs 180+), large angelfish (Queen/French/Gray - need 200+), foxface lo (gets too big at adult), large triggers, sharks. Multiple Yellow tangs (need 180+).

Browse mid-size reef fish

Live vendor inventory shipping overnight to all 50 states. Buyer Protection on every order.

Browse mid-size reef fish →

Frequently asked questions

Can I keep a pair of clowns + 2 tangs in 100g?

1 Yellow + 1 Kole works. Two Yellow tangs in 100g causes conspecific fighting - 180+ gallon required. Different body-shape tang species (Yellow + Kole + Hippo) work in 100g if added together.