Okay so my father has been keeping fish since he was a kid, but he does not always take care of his fish properly. What i mean is that he thinks that you don't need huge tanks to keep fish like gar, redtail cats, etc. He kind of follows the rule that fish don't have to grow so big and forbids or atleast discourages me to get big tanks / ponds to house fish that can potentially grow to monstrous sizes. Basically he thinks that a redtail can be housed in less than 100 gallon tank and expect it to grow to 3 feet. I need to prove him wrong, and btw i tried telling him about the things that can happen if he houses fish that potentially can grow large in a tank size not enough to support the sizes it can grow to. The way he keeps fish is more through experience than research ( he may do some research ). What i mean by this is that he buys fish then learns how to keep it and research is not really that much of a must. I need to prove him wrong, before he potentially flips out when i get a huge tank / pond. Any facts that anyone here can share to prove him wrong?