A hideout with two ways out — and that's the whole point. Most aggression in a cichlid tank happens when a fish gets cornered with nowhere to go. With two separate openings, a chased fish can duck in one side and slip straight out the other, so a single dominant fish can't trap it or guard the only door. The result is a noticeably calmer tank. Set into the aquarium, the stone also breaks up the line of sight between fish, which takes the heat out of territorial standoffs before they start. Which fish it's for Dwarf cichlids — Apistogramma, kribensis, shell-dwellers and similar Plecos, bettas, and other small community fish Shrimp, which use it as cover Best in 5–25 gallon tanks. Choose Medium for fuller-bodied fish. How to use Rinse before use. Place on a stable surface where fish can reach both openings. For aggressive species, position it so neither entrance can be guarded from a single spot. Details Sizes: Small: 15 × 9 × 9 cm (5.9 × 3.54 × 3.54 in) Medium: 17 × 13 × 10 cm (6.7 × 5.1 × 3.9 in) Material: high-temperature fired gray clay Safety Smooth edges inside and out. Inert, non-toxic ceramic, safe for fish, shrimp, and invertebrates. Tested on the Plecoceramics farm.