These are extremely hardy fish and although the labyrinth organ allows the fish to survive in oxygen depleted water, it is a common misconception that this makes water changes unnecessary. This is hardly the case as these fish will suffer the same tissue damage from built up toxins as any other fish. 

Water Changes: Weekly water changes of 25%.
Ph range: 6.0-8.0
Brackish: No
Water Movement: Weak, uncomfortable with strong currents.
Water Region: All - these fish will swim all over the aquarium.