Aquarium Stocking Calculator
Calculate how many fish your tank can safely support based on tank size and fish type.
Enter your aquarium size in gallons
This calculator provides general guidelines. Actual stocking depends on species, filtration, and maintenance habits. Visit our store for personalized advice.
Need Help Stocking Your Tank?
Visit our store for personalized stocking recommendations based on your specific tank and goals.
Visit StoreHow This Calculator Works
Tank Type Matters
Freshwater community tanks can hold more fish than saltwater reefs because reef fish are typically more territorial and produce more waste.
Filtration Factor
Better filtration means more capacity for fish. Heavy filtration can process more waste and maintain water quality with more fish.
Fish Size Counts
Larger fish need more space. One 6-inch fish takes up as much bioload as 3-5 small fish. Plan your stocking accordingly.
Stocking Tips from the Experts
Start Slow
Don't add all your fish at once. Add a few fish, wait 2-3 weeks for the tank to adjust, then add more. This prevents ammonia spikes.
Research Compatibility
Some fish just don't get along. Research your species before buying. Our staff can help you choose compatible tankmates.
Understock Rather Than Overstock
It's always better to have fewer fish than too many. Understocked tanks are easier to maintain and your fish will be healthier.
Consider Growth
That 1-inch pleco will grow to 12+ inches! Plan for adult sizes, not the size you see at the store.
Ready to Stock Your Tank?
Need Expert Advice?
Every tank is unique. Visit our store and talk to our experienced staff who can help you create the perfect aquarium.