I base my temps on an article by Paul Loiselle, when he went to Haiti to collect haitiensis, and took water parameter readings. In 3 different spots the water temp range was 82-86.
I also was in St Maartin a few years ago teaching my kids to snorkle, we started in a sheltered lagoon that felt like hot bath water, had to be in the 90s. I would liken this to small bodies of water I would suspect haitiensis of residing in.
Spent some time in Costa Rica and the Yucatan in the 80s and 90s, the cenotes and rivers are a bit cooler, due to depth, or water movement, hence the different requirements of say Dovii from Lago Arenal or tuba from a fast flowing river.
Whereas on Isla de Mujeres where I saw uropthalmus in the mangrove, temps fluctuated with tide, from 90s in the afternoon -70s at night, may be the reason uros are so tough.
I'd watch aggression very carefully in a 38 gal, aggression can be subtle in the haits pecking order, just a little on the low end leads to a stressed out bloater as Chris said.
Check out Joe Ferdenzis article in the 1995 TFH mag, he had what I consider great success loosing only 2 out of 5 haits, by using egg crate dividers, my track record in a 100 gal was paultry in comparison.