a 180 Gallon tank WILL NOT last the animal it's whole life. A dwarf caiman is a great croc to start with mainly because of size but you have to realize that its gonna be pretty aggressive. A dwarf caiman will certainly be more aggressive than any gator in it's weight class and thus harder to handle/manage. A 180 gallon tank will hold it from a baby for a nice little while......say around 2 feet. Remember you have to have plenty of space for excersise and thermoregulation. I have a 150 Gallon stock tank at home that was used to hold my gator. Hes about 3 feet now and thus that cannot work. You will have to make him a nice sized enclosure for him as an adult.
Read the crocodilian FAQ at:
www.crocodilian.com/crocfaq
and
http://www.flmnh.ufl.edu/cnhc/csp_ppal.htm- palpebrosus info