It depends on the species - while most Heterodontids do fine in that temperature range.
Port Jackson's do best in water temps below 70F. Captive studies on Port Jackson's have shown that - if they are kept at above 70F - they tend to grow faster than normal (maturing in about half the time), get much larger(over 4.5'), and have shortened life spans.
In keeping Heterodontids - it's very helpful in studing the water temps in their natural range. This way you can find the optimum water temps for each species.
For Example with California Horns - the seasonal change in water temps thru out their range - is from low of about 59-61F (Near Santa Barbara,CA-during winter) to a high 79-81F (Near Cabo San Lucas, Mexico -during summer). Therefore the average water temp is about 70F. So 65-75F is a good average range for optimum health of a pet California Horn Shark.
By the same token - in the Port Jackson' s home range - water temps range from a high of 75-77F (in the North- during Summer) to about a low of about 52-55F ( in the South -during Winter). So the average Water temp for Port Jackson's is about 64-65F. With an average water temp range for this species is about 59-70F.
