The Kachese are about 8-9 cm now (the biggest ones). The smallest are about 6 cm.
The tret has been in there for about seven months. He's about 7 cm long. He basically rules the tank, but only occasionally enforces that rule. The Tropheus do their usual thing and once in a while the Tret just barges in and scatters them. He's a great way to keep the alpha Tropheus male from completely dominating the tank. And the difference in shape and colour between the Tropheus and the Tret looks great.