To choose compatible fish, you should match adult size, temperament, and water needs first. Keep tropical fish with tropical species, and align temperature, pH, and hardness as closely…
Stocking & Tank Management
What Fish Can Live Together in the Same Tank?
You can keep fish together safely when you match their adult size, temperament, diet, and water needs. Peaceful community fish like neon or cardinal tetras, rasboras, zebra danios,…
Stocking & Tank Management
How to Calculate Fish Capacity for Any Tank Size
To calculate fish capacity for any tank size, first find the tank’s actual water volume in liters or gallons, using its shape and subtracting displacement from substrate and…
Stocking & Tank Management
How Many Fish Can You Put in a 30-Gallon Tank?
In a 30-gallon tank, you can usually keep about 12 to 25 small adult fish, but you should stock by adult size, not juvenile count. A conservative ceiling…
Stocking & Tank Management
How Many Fish Can You Put in a 20-Gallon Tank?
You can usually keep about 8–12 small fish in a 20-gallon tank to start, but the real limit depends on adult size, bioload, behavior, and filtration. A 20-gallon…
Stocking & Tank Management
How Many Fish Can You Put in a 10-Gallon Tank?
You can usually keep about 7 to 8 inches of adult small, slim-bodied fish in a 10-gallon tank, not a full 10 inches. That rule is only a…
Stocking & Tank Management
How to Stock a Fish Tank the Right Way
You should stock a fish tank slowly, using each fish’s adult size, shape, and behavior instead of inch-per-gallon rules. Add no more than about 25% of the planned…