Coralkinhonest saltwater & reef care

Free tool

Reef stocking & tank-size calculator

The most expensive beginner mistake is too many fish in too little water. Tell us your tank and your wish-list — we'll check each fish against its fact-checked minimum tank and shoal size, flag aggression and reef-safety clashes, and give you an honest read on how full the tank is.

1 · Your tank
…or work it out from tank dimensions (inches)

A rough guide — real filled volume is a little less than the glass dimensions (rock and sand displace water too).

2 · Your fish

Only fish with a fact-checked Coralkin care guide appear here — more as we source them.

An honest tool, not a promise. The minimum-tank, shoal-size and compatibility checks come straight from our fact-checked care guides. The "stocking level" gauge is adeliberately conservative, rough estimate — marine fish need far more water per inch than freshwater, and real capacity depends on your skimmer, filtration, flow and water changes. The only true judge is your water: test your nitrate and phosphate. For the full pairwise picture use thefish compatibility checker, and check your numbers against the reef parameter targets.