These guys grow to be about 6 inches long and do best in a 55 gallon aquarium or larger. They are known to be semi aggressive, so we recommend keeping them with larger fish that stay near the middle and top of the aquarium. A few examples of these are rainbow fish, gouramis or large tetras. Rainbow sharks usually do best as the only “shark” in the aquarium. This means we don’t recommend keeping them with red tail sharks or ghost sharks. All pictures shown are for illustration purposes only. Actual products may vary due to natural variation with livestock.