this is probably the wrong forum for it, as they are not cold water fish
anyhow, that being said, they are technically a catfish, although they are very active unlike most cats. thats why they will need a big tank, and tankmates who dont mind their constant movement
i have had luck getting them to eat just about anything.
i do not know the growth rate, but i have seen them as big as 30" and they get FAT, not just long like some cats. i think it just depends on the tank size and how often you feed them as to how quickly they grow.
water parameters are the same as any tropical fish