Reefing club

I was recently at a local aquarium club and we took a tour to see members 40g tank. He had a beautiful tank but I think It was overstocked. He had 7 fish. 2 of them were shrimp gobies 3 fish lived in caves and 2 were free swimming. He also had a golden dwarf moray eel (I went to see the tank because I am considering getting one and wanted to see one in person). There was a minor argument between the fellow reefers. Some said the tank was way over stocked. But the others said he was heavily stocked but the tank would be fine for know if no more additions were added. The tank had a 20g sump, 90g rated skimmer, in sump refugium, and bio-pelt reactor made from an old fluvial canister filter. There was too a marine biologist that took opposite sides of the argument. The tank had a small C.C. And 4 corals and 3 frags (That he was selling). Do you guys think his tank was overstocked? He tested the water in front of us and all of his levels were fine.