I put him in a 75 gallon with adult fancy goldfish. He swims right along with them and competes for the food as if there is no size difference. Very healthy and active but still has his baby bronze color. He will have to mature into his red and white coloring. I do mix in 1mm and 1.5 mm goldfish pellets and also feed spirulina flakes because he is too young to eat the same pellets as my full sized fancy goldfish.