I recently purchased a small Tiger Oscar, about 6 cm for my small tank, to be transfered when he got older. When I first puchased this tank, it was for Goldfish, which I eventually gave away. So my cats were used to sitting on the dresser I kept the tank on and drinking from the tank. Well, not 2 days after my new Oscar took residency in the tank, a cat came to get a small sip of water. To his surprise, my tiny Oscar grabbed ahold of his tongue and wouldn't let go! After a few seconds, my Oscar let him go and went plopping back into the tank. From then on, this kitty gets a drink at the water dish and doesn't mess with this bad fish, now almost 18 cm. He bites at fingers now, and has jumped free from his tank to the floor twice, only to emerge unharmed. This is a brave little oscar.