Freshwater Fish Compatibility Guide

Two peaceful species can still be poor tankmates if their temperature, adult size, feeding behavior, water movement, or space requirements conflict.

Plan for mature fish. Cichlids can become more territorial as they grow, pair, or spawn, and plecos vary enormously in adult size.

The temperature range should suit every species long term. Do not force one fish to live at the edge of its tolerance to accommodate another.

Fast, aggressive feeders can prevent calmer fish from maintaining condition. Observe whether every fish has reliable access to appropriate food.

Individual behavior varies. A divider, spare aquarium, or rehoming plan can be necessary even when a combination is generally considered compatible.