I have a 125g planted loach tank. I have 6 clowns, 8 yrs old 4-6 inches. 2 are much bigger than the rest and are very fat. 4 of mine were housed in a 55g hex tank for about 7 years before I adopted them from a family member. They have been kept in great conditions with a varried diet (always including some frozen or live foods). Currently I perform 40 gallon w/c every 4 days. Mine have grown very slowly in length, but all have grown thicker. They are my main residents. I have nerver been a heavy feeder because I think the high protein in fish foods is one of the biggest factors in nitrate and phosphate production. I actually fast my fish on Wednesdays. If you power feed they WILL grow faster. Just keep up with your w/c's........
that picture is awesome!