You don't need a 150 gallon tank for a reef tank or clownfish. I was keeping and breeding small species of anemone fish (clownfish) in tanks that were 18 inches long x 14 inches wide x 12 inches high. Bigger tanks are better, especially for the bigger species, but a 3 foot long tank will be fine for a pair of the largest anemone fish, some corals, and shrimp if you want shrimp.
Put a 1 inch layer of sand on the bottom, add some limestone rock, fill the tank with seawater (artificial or natural), get the filter running, add ammonia and let it cycle. Once it has cycled, add some corals and a young pr of anemone fish, and turn the lights on.
Feed the fish a couple of times a day, do water changes and clean the filter. Monitor the salinity (salt level), and in 6 months the anemone fish will start breeding. They lay eggs on rocks at the base of anemones of Leather Corals. The male guards the eggs and about 10 days later the eggs hatch and you get hundreds of little fry hanging out under the surface. The fry can be scooped out and put in a rearing tank that is blacked out on all sides, and the fry are fed on rotifers for the first couple of weeks, before adding newly hatched brineshrimp.
All anemone fish are male until they take over a territory, then they become female. If you can't find a pr (2 fish that hang out together all the time), then buy a small one and a bigger one. The big one will be female and the small one will stay male.
