1. Do Fish Really Sleep?

• Fish don’t close their eyes in the traditional sense, but they do enter a resting state.

• Their metabolism slows down, and their movements decrease.

• Most fish are not nocturnal; they are active during the day and rest at night.

• They can often be seen staying still or gently drifting in the water.

1. How and Where Do They Rest?

• They may stay motionless among plants, under rocks, or near the bottom.

• Some species (such as bettas) rest near the water surface.

• Catfish and bottom-dwellers usually rest on the substrate in the evening.

• Schooling fish often rest close to one another.

---

1. Lighting Control for Sleep Patterns

• The aquarium should have at least 8–10 hours of darkness each day.

• If a night light remains on continuously, fish cannot rest and may become stressed.

• Automatic timers are useful for creating a consistent light/dark cycle.

---

1. Inactivity Mistaken for Sleep

• Sick fish may also stay still, but this is usually accompanied by signs such as loss of appetite or changes in breathing.

• After overeating, fish may remain inactive for a short time.

• Very low water temperatures can make fish sluggish; in such cases, check the heater.

---

Conclusion
Fish need rest and energy recovery just like other living beings. Understanding their sleep-like behavior is crucial for maintaining a healthy day–night rhythm in the aquarium. Proper lighting schedules, a calm environment, and suitable tank conditions help fish establish a healthy rest routine.