It is great you are thinking about compatibility! Many factors matter when putting fish together.
1. Temperament
* Peaceful: Tetras, guppies, platys, mollies, corydoras catfish.
* Semi-aggressive: Angelfish, gouramis, discus.
* Aggressive: Many cichlids, oscars, piranhas.
2. Water Parameters
* pH, temperature, and hardness must match the species you choose.
3. Size and Space
* Ensure the tank is big enough for adult sizes. Overcrowding causes stress and disease.
4. Diet
* Herbivores, carnivores, and omnivores all need access to a varied diet.
5. Social Behavior
* Some fish need schools; others prefer to be alone.
Research is key. Use resources like FishLore, Seriously Fish, and Aquarium Advice. Check temperament, tank size, water parameters, diet, and social behavior.
Example compatible community tank: Neon tetras, corydoras catfish, ghost shrimp, java fern, and anubias.
Remember: Even compatible fish can become territorial if overcrowded or stressed. Observe closely and be ready to separate or re-home if needed.