Ideal Tank Size for Flowerhorns

You should provide your flowerhorn with more room than it needs.
Many newbie hobbyists fail to realize that tank size is one of the biggest factors which promote flowerhorn head growth and health.

In choosing the ideal tank for a flowerhorn, size and age of the fish must be considered.
Louhans are just too aggressive and should be kept in a separate aquarium alone.
Advantages of Large Aquariums
  • fairly constant water temperature
  • cleaner water/less frequent need for water change
  • better nitrogen cycle parameters, e.g. less ammonia per gallon of water
  • more room for the fish to move around/more physical activity

Aquarium Size for Juvenile and Small Louhans
For a juvenile (2-3 inches), the minimum aquarium capacity is 30 gallons. This is ideal for flowerhorn head growth for juvenile fish.

Since louhans grow very fast, many hobbyists skip the 30-gallon and use the 50-gallon aquarium instead. Choosing the 50-gallon aquarium saves time and effort in moving your set-up and fish when it reaches 4-5 inches (small size). It also saves your fish from the stress of moving and adjusting to a new container again.

Tank Size for Medium-Size and Large-Size Flowerhorns
Recent types of flowerhorns rarely reach extra large-size except for the Kamfa which is a good thing as there is no longer a need for very large containers.

For a medium-size (5-6 inches), you may still use a 50-gallon container. However, many would hold that a 50-gallon container is not enough for a medium-size louhan. At this point, 70-gallon aquariums are more ideal.

For large fishes, 70-gallon containers are standard practice. A larger aquarium, however, is better.

Flowerhorn Size
Recommended Tank Sizes
Fry (around 1 inch)
15 gal. (12” x 12” x 24”) Ideal
20 gal. (12” x 16” x 24”) Ideal
Juvenile (2-3 inches)
20 gal. (12” x 16” x 24”) Good
30 gal. (16” x 16” x 24”) Ideal
50 gal. (18” x 18” x 36”) Best
Small (4-5 inches)
50 gal. (18” x 18” x 36”) Ideal
70 gal. (18” x 18” x 48”) Best
Medium (5-6 inches)
50 gal. (18” x 18” x 36”) Good
70 gal. (18” x 18” x 48”) Best
Large (7 or more inches)
70 gal. (18” x 18” x 48”) Ideal