I think I also had a French Angel and Moorish Idol in there with him along with a few other fish, one of them a figure 8 puffer.
That was long before they invented tang police and probably before they were born.
I can't bring up my log book page now because my photobucket sharing site is down but I have posted it many times.
At that time, 1971, a 40 gallon salt tank was considered big and no one had salt water fish so we didn't know anything about tank size.
Those fish lived but their growth was stunted.
At the time I didn't know how big those fish were supposed to get and it was considered a success to even keep anything alive, much less care if the tank was big enough.
To answer your question, those fish will live, but be stunted.
Some fish will continue to grow no matter the size of the tank.
Remora,s, flounders, sea robins and I am sure others will keep growing and then die when they can't get enough oxygen from the water.
I am not quoting the internet, I have kept quite a few of all those fish.