So I've recently inherited a large tank from my dad, who passed away in April. I'm planning on using it to start a sorority, but I'm a little nervous about one thing. The tank used to house Tiger Oscars, who got ended up getting hole in the head and passing away. The tank is large, but I don't know exactly how large. I know it's over 30 gallons, but it could be 50 gallons. I'm just not sure. Anyways, what should I do to clean it out? Is Hole in the Head contagious? The tank hasn't been used in over two years, I know.