1. Aquarium Sand

• Fine-grained, usually available in white, black, or natural colors.

• Ideal for bottom-dwelling fish (such as catfish or plecos) since it doesn’t harm their fins.

• Provides an aesthetic appearance and tends to reduce algae buildup.

• Very compact sand can hinder root growth and create oxygen-deprived zones.

• During cleaning, siphoning must be done carefully as particles scatter easily.

1. Aquarium Gravel

• Coarser and rounder-grained, available in many different colors and sizes.

• Allows better water circulation between pieces, supporting beneficial bacterial colonies.

• Suitable for plant-free or decorative aquariums.

• Uneaten food can get trapped between stones, leading to odor and water quality issues over time.

• Avoid sharp-edged gravel, which can injure bottom-dwelling fish.

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1. Plant Substrates (Aquarium Soil)

• Specially formulated for planted aquariums.

• Nutrient-rich, supporting root development and plant growth.

• Often recommended to be covered with sand or fine gravel.

• May cause temporary cloudiness when first used.

• Ideal for CO₂-supported planted tanks.

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1. Which Substrate to Choose?

• For fish-only, plant-free aquariums: sand or gravel is sufficient.

• For tanks with bottom dwellers: soft sand is preferable.

• For planted aquariums: nutrient-rich plant soil should be used and topped with sand.

• For mixed tanks: a base layer of plant soil with sand on top is a good combination.

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Conclusion
The aquarium substrate is far more than just decoration. The material chosen directly affects the tank’s long-term health, cleanliness, and the comfort of its inhabitants. When selecting a substrate, consider both the fish species and the presence of live plants—choosing sand, gravel, or plant soil according to their needs.